Apparatus and Method for Generating a Magnetic Field

Abstract

A first magnetic field for application to body tissue is generated via a first inductor. A second magnetic field is also generated via a second inductor. Connecting circuitry, including at least first and second branches, is provided between an electric storage device such as a capacitor, or a capacitor arrangement comprising at least a first capacitor, and the first and second inductors. A switch forming part of the first branch electrically connects the electric storage device to the first inductor enabling electrical current to flow through the first branch and the first inductor, thereby causing the first inductor to generate the first magnetic field. The current flowing through the first branch represents a first direction of flow with respect to the electric storage device. A switch forming part of the second branch electrically connects the electric storage device to the second inductor enabling current to flow between the electric storage device and the second inductor through the second branch. The current flowing through the second branch represents a second direction of flow with respect to the electric storage device.

Claims

1. An apparatus for generating a magnetic field for application to body tissue, the apparatus comprising: an electric storage device for storing electrical energy; a first inductor for generating a first magnetic field for application to body tissue; a second inductor for generating a second magnetic field; connecting circuitry between the electric storage device and the first and second inductors, wherein the connecting circuitry comprises a first branch between the electric storage device and the first inductor and a second branch between the electric storage device and the second inductor; a first switching device, wherein the first switching device forms part of the first branch, wherein the first switching device is configured to electrically connect the electric storage device to the first inductor in order to enable electrical current to flow through the first branch and through the first inductor, caused by the electrical energy stored by means of the electric storage device, thereby causing the first inductor to generate the first magnetic field, wherein the electrical current flowing through the first branch represents a first current direction of current flow with respect to the electric storage device; and a second switching device, wherein the second switching device forms part of the second branch, wherein the second switching device is configured to electrically connect the electric storage device to the second inductor in order to enable electrical current to flow through the second branch and through the second inductor, caused by the electrical energy stored by means of the electric storage device, thereby causing the second inductor to generate the second magnetic field, wherein the electrical current flowing through the second branch represents a second current direction of current flow with respect to the electric storage device, wherein the second current direction of current flow is opposite the first current direction of current flow.

2. The apparatus according to claim 1, wherein the first and second inductors are not connected in series.

3. The apparatus according to claim 1, wherein the first switching device is configured to enable current flow with respect to the electric storage device only in the first current direction; and wherein the second switching device is configured to enable current flow with respect to the electric storage device only in the second current direction.

4. The apparatus according to claim 1, wherein the second inductor is configured such that the second magnetic field is also for application to body tissue.

5. The apparatus according to claim 1, wherein the first inductor comprises at least a first set of turns, preferably at least a first set of generally circular, hexagonal or rectangular turns, wherein the turns of the first set of turns are preferably arranged such that each turn generates a contribution towards the first magnetic field when the electrical current flows through the first inductor, wherein the contributions generated by each turn are superimposed in a positive manner, wherein the first inductor is disposed within a first casing connected to a first conduit through which extends at least a first cable for supplying electrical power to the first set of turns, and wherein the second inductor is not disposed within said first casing.

6. The apparatus according to claim 5, wherein the second inductor comprises at least a second set of turns, preferably at least a second set of generally circular, hexagonal or rectangular turns, wherein the turns of the second set of turns are preferably arranged such that each turn generates a contribution towards the second magnetic field when the electrical current flows through the second inductor, wherein the contributions generated by each turn are superimposed in a positive manner, wherein the second inductor is disposed within a second casing connected to a second conduit through which extends at least a second cable for supplying electrical power to the second set of turns, and wherein the first inductor is not disposed within said second casing.

7. The apparatus according to claim 1, wherein the first inductor is wound on a first core and the second inductor is wound on a second core different from the first core.

8. The apparatus according to claim 1, wherein the first inductor and the second inductor are moveable independently from each other.

9. The apparatus according to claim 1, wherein a first inductance of the first inductor and/or a second inductance of the second inductor is one of discretely variable and substantially continuously variable.

10. The apparatus according to claim 1, wherein the electric storage device comprises a pulse capacitor which can be charged by a charging circuit.

11. A method of generating a magnetic field, the method comprising: providing an apparatus according to claim 1; storing electrical energy in the electric storage device; switching the first switching device so as to electrically connect the electric storage device to the first inductor and thereby enabling electrical current to flow through the first branch and the first inductor in the first current direction of current flow with respect to the electric storage device, caused by the electrical energy stored by means of the electric storage device, thereby causing the first inductor to generate the first magnetic field; and switching the second switching device so as to electrically connect the electric storage device to the second inductor and thereby enabling electrical current to flow through the second branch and the second inductor in the second current direction of current flow with respect to the electric storage device, caused by the electrical energy stored by means of the electric storage device, thereby causing the second inductor to generate the second magnetic field.

12. The method according to claim 11, wherein the apparatus is operated in a pulsed manner, wherein the electrical current flowing through the first branch represents a first half pulse and wherein the electrical current flowing through the second branch represents a second half pulse, the first half pulse and the second half pulse together forming a pulse.

13. The method according to claim 12, wherein switching the second switching device comprises switching the second switching device after a delay after an end of the first half pulse.

14. The method according to claim 13, wherein the first half pulse has a first duration, wherein the delay is longer than the first duration.

15. The method according to claim 11, further comprising bringing the first inductor into proximity with body tissue, or bringing the body tissue into proximity with the first inductor, so that the first magnetic field is present in said body tissue.

16. The method according to claim 15, further comprising varying the first magnetic field in the body tissue so as to generate a voltage in the body tissue or to cause a movement of charges in the body tissue.

17. The method according to claim 16, wherein the generated voltage or the movement of charges in the body tissue is sufficient to cause a neural reaction or a cellular physiological reaction, in particular a muscle reaction, in the body tissue, wherein preferably the voltage or the movement of charges is sufficient to cause a therapeutic effect.

18. The method according to claim 15, further comprising bringing the second inductor into proximity with the body tissue, or bringing the body tissue into proximity with the second inductor, so that the second magnetic field is present in said body tissue.

19. An apparatus for use with a first inductor and a second inductor, the first inductor for generating a magnetic field for application to body tissue, the apparatus comprising: an electric storage device for storing electrical energy; a first terminal for connection to the first inductor for generating a first magnetic field for application to body tissue; a second terminal for connection to the second inductor for generating a second magnetic field; connecting circuitry between the electric storage device and the first and second terminals, wherein the connecting circuitry comprises at least a first branch leading to the first terminal and a second branch leading to the second terminal; a first switching device, wherein the first switching device forms part of the first branch, wherein the first switching device is configured to electrically connect the electric storage device to the first terminal so as to enable electrical current to flow through the first branch and through the first inductor via said first terminal when the first inductor is connected to the apparatus via said first terminal, caused by the electrical energy stored by means of the electric storage device, thereby causing the first inductor to generate the first magnetic field, wherein the electrical current flowing through the first branch represents a first current direction of current flow with respect to the electric storage device; and a second switching device, wherein the second switching device forms part of the second branch, wherein the second switching device is configured to electrically connect the electric storage device to the second terminal so as to enable electrical current to flow through the second branch and through the second inductor via said second terminal when the second inductor is connected to the apparatus via said second terminal, caused by the electrical energy stored by means of the electric storage device, thereby causing the second inductor to generate the second magnetic field, wherein the electrical current flowing through the second branch represents a second current direction of current flow with respect to the electric storage device, wherein the second current direction of current flow is opposite the first current direction of current flow.

Description

[0438] Some embodiments of the invention will now be described by way of example only and with reference to the accompanying drawings, in which:

[0439] FIG. 1 schematically shows a circuit diagram of a device for generating an alternating magnetic field known to the inventor (and not admitted as prior art).

[0440] FIG. 2 schematically shows a circuit diagram of an apparatus for generating a magnetic field in accordance with an embodiment of the present disclosure.

[0441] FIG. 3 schematically shows a circuit diagram of an apparatus for generating a magnetic field in accordance with an embodiment of the present disclosure.

[0442] FIG. 4 schematically shows a circuit diagram of an apparatus for generating a magnetic field in accordance with an embodiment of the present disclosure.

[0443] FIG. 5 schematically shows an apparatus for generating a magnetic field in accordance with an embodiment of the present disclosure.

[0444] FIG. 6 shows a flowchart illustrating a method in accordance with an embodiment of the present disclosure.

[0445] FIG. 7 shows a diagram in which the current through the first inductor is plotted over time, in accordance with an embodiment of the present disclosure.

[0446] FIG. 8 schematically shows a circuit diagram of an apparatus for generating a magnetic field in accordance with an embodiment of the present disclosure.

[0447] FIG. 9 schematically shows a circuit diagram of an apparatus for generating a magnetic field in accordance with an embodiment of the present disclosure.

[0448] FIG. 10 schematically shows a circuit diagram of an apparatus for generating a magnetic field in accordance with an embodiment of the present disclosure.

[0449] FIG. 11 schematically shows an apparatus for generating a magnetic field in accordance with an embodiment of the present disclosure.

[0450] FIG. 12 shows a flowchart illustrating a method in accordance with an embodiment of the present disclosure.

[0451] FIG. 13 shows a diagram in which the current through the first inductor is plotted over time, in accordance with an embodiment of the present disclosure.

[0452] FIG. 14 schematically shows a circuit diagram of an apparatus for generating a magnetic field in accordance with an embodiment of the present disclosure.

[0453] FIG. 15 schematically shows a circuit diagram of an apparatus for generating a magnetic field in accordance with an embodiment of the present disclosure.

[0454] FIG. 16 schematically shows a circuit diagram of an apparatus for generating a magnetic field in accordance with an embodiment of the present disclosure.

[0455] FIG. 17 schematically shows a circuit diagram of an apparatus for generating a magnetic field in accordance with an embodiment of the present disclosure.

[0456] FIG. 18 schematically shows an apparatus for generating a magnetic field in accordance with an embodiment of the present disclosure.

[0457] FIG. 19 shows a flowchart illustrating a method in accordance with an embodiment of the present disclosure.

[0458] FIG. 20 shows a diagram in which the current through the (first) inductor is plotted over time, in accordance with an embodiment of the present disclosure.

[0459] FIG. 21 schematically shows a circuit diagram of an apparatus for generating a magnetic field in accordance with an embodiment of the present disclosure.

[0460] FIG. 22 schematically shows a circuit diagram of an apparatus for generating a magnetic field in accordance with an embodiment of the present disclosure.

[0461] FIG. 23 schematically shows an apparatus for generating a magnetic field in accordance with an embodiment of the present disclosure.

[0462] FIG. 24 shows a flowchart illustrating a method in accordance with an embodiment of the present disclosure.

[0463] FIG. 25 shows a diagram in which the current through the (first) inductor is plotted over time, in accordance with an embodiment of the present disclosure.

[0464] FIG. 26 schematically shows a circuit diagram of an apparatus for generating a magnetic field in accordance with an embodiment of the present invention.

[0465] FIG. 27 schematically shows an apparatus for generating a magnetic field in accordance with an embodiment of the present invention.

[0466] FIG. 28 schematically shows an apparatus for generating a magnetic field in accordance with an embodiment of the present invention.

[0467] FIG. 29 schematically shows an apparatus for generating a magnetic field in accordance with an embodiment of the present invention.

[0468] FIG. 30 shows a diagram in which the current through the first inductor and the second inductor is plotted over time, in accordance with an embodiment of the present invention.

[0469] FIG. 31 shows a flowchart illustrating a method in accordance with an embodiment of the present invention.

[0470] FIG. 2 schematically shows a circuit diagram of an apparatus for generating a magnetic field in accordance with an embodiment of the present disclosure. The circuit diagram shown in FIG. 2 is similar to that shown in FIG. 1. The above explanations regarding the device shown in FIG. 1 therefore also apply to the circuit diagram shown in FIG. 2 and will not be repeated here. Elements shown in FIG. 2 corresponding to elements shown in FIG. 1 carry the same reference signs reduced by 100. However, it should be noted that various modifications are possible. For example, while in many embodiments the source of electrical energy 7 (e.g. a voltage source 7) may be mains powered, it can alternatively be non-mains powered and may, for example, comprise a battery or a battery arrangement comprising one or more batteries. Switching device 3 is shown as a thyristor, but other switching devices can be used, as has been explained above. Electric component 4 in the second branch 6 is shown as a diode, but other electric components or an assembly of electric components, in particular electronic components or an assembly of electronic components, can be used, as has been explained above. However, in the interest of a compact explanation, the description of the circuit diagram shown in FIG. 2 will proceed using the same terminology as has been used in connection with FIG. 1.

[0471] Further, a charging circuit comprising a source of electrical energy 7 and a switching device 8 is shown for better understanding, although the disclosure includes embodiments without such a charging circuit (but which can be used together with such a charging circuit, in particular which can be electrically connected to such a charging circuit).

[0472] The second branch 6 shown in FIG. 2 includes a second inductor 9 connected in series with diode 4. Electrical current flowing between the first inductor 2 and the capacitor 1 through the second branch 6 will also flow through the second inductor 9. Considering the current flow through the first inductor 2 and the second branch 6 and the capacitor 1, the second inductor 9 is effectively connected in series with the first inductor 2. No such additional inductor forms part of the first branch 5, and therefore the inductance of the second branch 6 is higher than the inductance of the first branch 5, in particular significantly higher. Therefore, when considering the capacitor 1, the first inductor 2 and either the first branch 5 or the second branch 6 as a resonant circuit, it can be seen that the frequency of the resonant circuit including the second branch 6 is (significantly) lower than the frequency of the resonant circuit including the first branch 5.

[0473] FIG. 3 schematically shows a circuit diagram of an apparatus for generating a magnetic field in accordance with an embodiment of the present disclosure. The embodiment shown in FIG. 3 is similar to that shown in FIG. 2, and the same explanations provided in connection with FIG. 2 also apply to the embodiment shown in FIG. 3. Like components carry like reference signs. FIG. 3 additionally shows circuitry for bypassing or short-circuiting the second inductor 9. This bypass circuitry is connected to the two terminals of the second inductor 9 and includes a further switching device 10 to enable the bypass circuitry to selectively bypass the second inductor 9. When the further switching device 10 is closed (or conductive), any electrical current flowing through the second branch 6 will predominantly or (almost) exclusively flow through the bypass circuitry, thereby substantially preventing current from flowing through the second inductor 9. In this way, the total inductance of the second branch 6 can be changed between a maximum value (further switching device 10 open) and a minimum value (further switching device 10 closed). When the further switching device 10 is closed, the inductance of the second branch 6 may be similar to the inductance of the first branch 5.

[0474] FIG. 4 schematically shows a circuit diagram of an apparatus for generating a magnetic field in accordance with an embodiment of the present disclosure. The embodiment shown in FIG. 4 is similar to that shown in FIG. 3, and the same explanations provided in connection with FIG. 3 also apply to the embodiment shown in FIG. 4. Like components carry like reference signs. FIG. 4 additionally shows a further inductor 11 forming part of the second branch 6 and connected in series with the second inductor 9 (and the diode 4). The circuit diagram shown in FIG. 4 additionally includes further circuitry for bypassing or short-circuiting the further inductor 11. This further bypass circuitry is connected to the two terminals of the further inductor 11 and includes a further switching device 12 to enable the further bypass circuitry to selectively bypass the further inductor 11. When the further switching device 12 is closed (or conductive), any electrical current flowing through the second branch 6 will predominantly or (almost) exclusively flow through the further bypass circuitry, thereby substantially preventing current from flowing through the further inductor 11. In this way, the total inductance of the second branch 6 can be varied.

[0475] Using the two further switching devices 10 and 12, the total inductance of the second branch 6 can be changed between a maximum value (both further switching devices 10 and 12 open or non-conductive) and a minimum value (both further switching devices 10 and 12 closed or conductive). When both further switching devices 10 and 12 are closed, the inductance of the second branch 6 may be similar to the inductance of the first branch 5. When only one of the further switching devices 10 and 12 is closed and the other is open, only one of the second inductor 9 and the further inductor 11 will be bypassed, and accordingly the total inductance of the second branch 6 will be at an intermediate value between the minimum value and the maximum value.

[0476] According to a variant of the embodiment shown in FIG. 4, the bypass circuitry associated with either the second inductor 9 or the further inductor 11 can be omitted. The respective inductor will therefore be permanently connected in series with the diode 4, whereas the other of the second inductor 9 and the further inductor 11 (the bypass circuitry of which is not omitted) can selectively be bypassed using its associated bypass circuitry.

[0477] According to a further variant of the embodiment shown in FIG. 4, yet further inductors can be added to the second branch 6 in series with the diode 4, the second inductor 9 and the further inductor 11. Each of these yet further inductors may or may not have their associated bypass circuitry similar to the bypass circuitry associated with the second inductor 9 and the further inductor 11.

[0478] According to a variant of any of the embodiments described with reference to FIGS. 2, 3 and 4 (or any of the variants already explained above), any one or more of the second inductor 9, the further inductor 11 and the yet further inductors (if provided) may comprise inductors with a variable inductance. Details of inductors with a variable inductance have already been explained above.

[0479] In a further development of this variant, only one of the inductors in the second branch 6 is of variable inductance, for example the second inductor 9. Nevertheless, by suitable choice of the (maximum) inductance of the second inductor 9 and of the inductance of the further inductors in the second branch 6, the total inductance of the second branch 6 can be adjustable over a relatively wide range, in particular in small steps or (substantially) continuously. In this further development, each of the further inductors is provided with associated bypass circuitry. The second inductor 9 of variable inductance may or may not be provided with associated bypass circuitry. If the inductances of the second inductor (L2) and of the further inductors (L3, L4, L5, L6 etc.) are chosen according to a ratio of 1:1:2:4:8 etc., the lowest value of total inductance of the second branch 6 can be achieved if the third inductor (of inductance L3) and any further inductors (of inductance L4, L5, L6 etc.) are bypassed and the variable inductance (L2) of the second inductor 9 is adjusted to a minimum value L2min. By adjusting the variable inductance L2 of the second inductor 9 over its adjustable range to a maximum value L2max, the total inductance of the second branch 6 can be adjusted from L2min to L2max. If (only) the third inductor is not bypassed (and the fourth and any further inductors are bypassed), the total inductance of the second branch 6 can be adjusted from L3+L2min to L3+L2max by adjusting the variable inductance L2 of the second inductor 9 over its adjustable range. If (only) the fourth inductor is not bypassed (and the third, fifth and any further inductors are bypassed), the total inductance of the second branch 6 can be adjusted from L4+L2min to L4+L2max. The next adjustable range of the total inductance can be achieved by not bypassing the third and fourth inductor and bypassing the fifth and any further inductors, and so on. If the relative inductances of the second inductor and of the further inductors are chosen according to the above ratio, and further assuming that the variable inductance L2 of the second inductor 9 can be adjusted down to substantially zero (L2min=0), the total inductance of the second branch 6 can be adjusted (in discrete steps or substantially continuously) from substantially 0 to a maximum total inductance corresponding to the sum of all inductances of the inductors forming part of the second branch 6, i.e. L2max+L3+L4+L5 etc.

[0480] According to a further variant, which can be based on any of the above embodiments or variants, the second and/or any further inductors (together with any associated bypass circuitry) are included in the first branch 5, rather than the second branch 6.

[0481] FIG. 5 schematically shows an apparatus for generating a magnetic field in accordance with an embodiment of the present disclosure. This is closely based on the embodiment shown in FIG. 3. However, the charging circuit shown in FIG. 3 is not shown in FIG. 5. Instead, FIG. 5 shows the capacitor 1 and the first and second branches 5 and 6 incorporated in a housing or cabinet 16 (electrically insulated from electric components and circuitry accommodated by cabinet 16). A terminal 19 for connection to an external charging circuit is provided on the cabinet 16 for the purpose of charging the capacitor 1. In a variant, the charging circuit, for example as shown in FIG. 3, can also be incorporated in the cabinet 16.

[0482] Cabinet 16 is provided with two further terminals, 17 and 18. Terminal 17 is connected to the first branch 5 and second branch 6, whereas terminal 18 is connected to a common ground potential. In the embodiment shown in FIG. 5, terminal 18 is connected to the ground connection for the capacitor 1 via a line running within the cabinet 16.

[0483] FIG. 5 shows the first inductor 2 as a separate entity from cabinet 16 and its contents. The first inductor 2 is accommodated in a casing 13, which is attached to a conduit 14. Conduit 14 accommodates a cable 15, which is electrically connected to the first inductor 2, in particular to at least one set of turns of inductor 2, and which can be connected to the terminal 17 as indicated by a dashed line. In the embodiment shown in FIG. 5, the inductor 2 can also be connected, via a second cable, to the ground terminal 18 on cabinet 16.

[0484] As a variant of the embodiment shown in FIG. 5, the first inductor 2 could be connected to a ground potential via a separate line, i.e. not via the cabinet 16. In this case, the ground terminal 18 and the internal connection to ground could be omitted.

[0485] In further variants, features of the embodiment shown in FIG. 5 can be combined with the embodiments shown in FIGS. 2 and 4 or any variants described herein. Further, in any of the above embodiments or variants, any or all connections to ground could be omitted and replaced by an electrical connection between the different portions of the circuit. For example, in FIG. 2, the three connections to ground (triangles towards the bottom of the figure) could be replaced by an interconnection so that the (in FIG. 2 lower side of) capacitor 1, first inductor 2 and voltage source 7 are electrically connected.

[0486] In any of the above embodiments or variants, the polarities of the individual components can be reversed so that, for example, the negative terminal of the voltage source 7 is connected, via the switching device 8, to the first branch 5, second branch 6 and capacitor 1. The polarities of the thyristor 3 and the diode 4 would then also be reversed. Further, as has already been mentioned, the inventor has appreciated that the components and interconnections described in connection with the present disclosure are not “ideal” in the electrical sense. Enabled by the present disclosure, one skilled in the art will be able to make appropriate adjustments to allow for this. This applies in particular, but not exclusively, to the variant described above in which inductors having inductances according to a ratio of 1:1:2:4:8 etc. can be used. Appropriate adjustments can be made so as to take parasitic inductances into account, for example.

[0487] FIG. 6 shows a flowchart illustrating a method in accordance with an embodiment of the present disclosure. After the start 90 of the method, any one of the apparatuses described above is provided (91). Electrical energy is then (92) stored in the electric storage device, in particular the capacitor 1. Thereafter, the switching device 3, in particular the thyristor 3, is switched (93) into a conductive or “ON” state so as to electrically connect the electric storage device 1 to the first inductor 2. This enables electrical current to flow through the first branch 5 and through the first inductor 2, caused by the electrical energy stored by the electric storage device 1, thereby causing the first inductor 2 to generate a magnetic field. This current flow may represent a first half pulse or half wave. At the end of the first half pulse or half wave, electrical current is then enabled (94) to flow between the electric storage device 1 and the first inductor 2 through the second branch 6 via the electric component or assembly of electric components 4. This current flow may represent a second half pulse or half wave. Assuming the second and any further inductors 9, 11 are not bypassed or short-circuited, electrical current will also flow through the second and any further inductors 9, 11 during this second half pulse or half wave. At the end of the second half pulse or half wave, the method may end (95). Alternatively, the method or part thereof may be repeated. In particular, the switching device or thyristor 3 can again be switched (93) into the conductive or “ON” state etc. Electrical energy may also again be stored (92) in the electric storage device 1. In particular, the capacitor 1 may be recharged to its initial charging state, e.g. to compensate for dissipation of electrical energy in the apparatus.

[0488] FIG. 7 shows a diagram in which the current through the first inductor 2 is plotted over time, in accordance with an embodiment of the present disclosure. A circuit which might result in the diagram of FIG. 7 could be the circuit shown in FIG. 2, except that the second inductor 9 would be located in the first branch 5 (in series with the switching device 3), rather than the second branch 6. The first half pulse shown in FIG. 7 exhibits a slower rise and fall of the current through the first inductor 2 than the second half pulse. This is due to the higher total inductance during the first half pulse (total inductance=inductance of first inductor 2+inductance of second inductor 9) when compared with the total inductance during the second half pulse (total inductance=inductance of first inductor 2).

[0489] FIG. 8 schematically shows a circuit diagram of an apparatus for generating a magnetic field in accordance with an embodiment of the present disclosure. The circuit diagram shown in FIG. 8 is similar to that shown in FIG. 2. The above explanations regarding the device shown in FIG. 2 therefore also apply to the circuit diagram shown in FIG. 8 and will not be repeated here. Where elements shown in FIG. 8 have substantially the same function as elements shown in FIG. 2, these carry the same reference signs as in FIG. 2. Where elements shown in FIG. 8 are generally similar to elements shown in FIG. 2 but are different, for example in terms of their function or position within the circuit, these carry the reference signs as in FIG. 2 but increased by 300.

[0490] In contrast to the embodiment shown in FIG. 2, the second branch 6 does not include an additional inductor which does not (also) form part of the first branch 5. Instead, the circuit shown in FIG. 8 includes a second inductor 309 connected in series with the first inductor 2. Electrical current flowing between the first inductor 2 and the capacitor 1 will also flow through the second inductor 309, regardless of whether the current flows through the first branch 5 or the second branch 6. In other words, the second inductor 309 is not only connected in series with the first inductor 2 but also with each of the switching device 3 and the diode 4 (or, more precisely, in series with the parallel connection that comprises the switching device 3 and the diode 4). One could also say that the second inductor 309 forms part of both the first branch 5 and the second branch 6.

[0491] The total inductance of the (resonant) circuit between (and including) the capacitor 1 and the first inductor 2 corresponds to the sum of the inductances of the first inductor 2 and the second inductor 309 (as well as any other inductance, including parasitic inductances, that may be present in the circuit and which are not shown in FIG. 8). Accordingly, the frequency of this (resonant) circuit is different from the frequency of the (resonant) circuit shown in FIG. 1, i.e. if the second inductor 309 was not present. The frequency of the (resonant) circuit shown in FIG. 8 can therefore be influenced by selecting different values of inductance for the second inductor 309.

[0492] FIG. 9 schematically shows a circuit diagram of an apparatus for generating a magnetic field in accordance with an embodiment of the present disclosure. The embodiment shown in FIG. 9 is similar to that shown in FIG. 8, and the same explanations provided in connection with FIG. 8 also apply to the embodiment shown in FIG. 9. Like components carry like reference signs. FIG. 9 additionally shows circuitry for bypassing or short-circuiting the second inductor 309. This bypass circuitry is connected to the two terminals of the second inductor 309 and includes a further switching device 310 to enable the bypass circuitry to selectively bypass the second inductor 309. When the further switching device 310 is closed (or conductive), any electrical current flowing through the first inductor 2 will predominantly or (almost) exclusively flow through the bypass circuitry, thereby substantially preventing current from flowing through the second inductor 309. In this way, the total inductance of the (resonant) circuit between (and including) the capacitor 1 and the first inductor 2 can be changed between a maximum value (further switching device 310 open) and a minimum value (further switching device 310 closed). When the further switching device 310 is closed, the inductance of the (resonant) circuit may be similar to that of the corresponding circuit portion of FIG. 1 (i.e. as if the second inductor 309 was not present.

[0493] FIG. 10 schematically shows a circuit diagram of an apparatus for generating a magnetic field in accordance with an embodiment of the present disclosure. The embodiment shown in FIG. 10 is similar to that shown in FIG. 9, and the same explanations provided in connection with FIG. 9 also apply to the embodiment shown in FIG. 10. Like components carry like reference signs. FIG. 10 additionally shows a further inductor 311 connected in series with the first inductor 2 and the second inductor 309. Electrical current flowing between the first inductor 2 and the capacitor 1 will also flow through the further inductor 311, regardless of whether the current flows through the first branch 5 or the second branch 6. In other words, the further inductor 311 is not only connected in series with the first and second inductors 2, 309 but also with each of the switching device 3 and the diode 4 (or, more precisely, in series with the parallel connection that comprises the switching device 3 and the diode 4). The circuit diagram shown in FIG. 10 additionally includes further circuitry for bypassing or short-circuiting the further inductor 311. This further bypass circuitry is connected to the two terminals of the further inductor 311 and includes a further switching device 312 to enable the further bypass circuitry to selectively bypass the further inductor 311. When the further switching device 312 is closed (or conductive), any electrical current flowing through the first inductor 2 will predominantly or (almost) exclusively flow through the further bypass circuitry, thereby substantially preventing current from flowing through the further inductor 311. In this way, the total inductance of the resonant circuit can be varied.

[0494] Using the two further switching devices 310 and 312, the total inductance of the resonant circuit can be changed between a maximum value (both further switching devices 310 and 312 open or non-conductive) and a minimum value (both further switching devices 310 and 312 closed or conductive). When both further switching devices 310 and 312 are closed, the total inductance of the resonant circuit may be similar to that of the corresponding circuit portion of FIG. 1 (i.e. as if the second inductor 309 and the further inductor 311 was not present. When only one of the further switching devices 310 and 312 is closed and the other is open, only one of the second inductor 309 and the further inductor 311 will be bypassed, and accordingly the total inductance of the resonant circuit will be at an intermediate value between the minimum value and the maximum value.

[0495] According to a variant of the embodiment shown in FIG. 10, the bypass circuitry associated with either the second inductor 309 or the further inductor 311 can be omitted. The respective inductor will therefore be permanently connected in series with the first inductor 2, whereas the other of the second inductor 309 and the further inductor 311 (the bypass circuitry of which is not omitted) can selectively be bypassed using its associated bypass circuitry.

[0496] According to a further variant of the embodiment shown in FIG. 10, yet further inductors can be added in series with the first and second inductors 2, 309 and the further inductor 311 (and in series with the parallel connection that comprises the switching device 3 and the diode 4). Each of these yet further inductors may or may not have their associated bypass circuitry similar to the bypass circuitry associated with the second inductor 309 and the further inductor 311.

[0497] According to a variant of any of the embodiments described with reference to FIGS. 8, 9 and 10 (or any of the variants already explained above), any one or more of the second inductor 309, the further inductor 311 and the yet further inductors (if provided) may comprise inductors with a variable inductance. Details of inductors with a variable inductance have already been explained above.

[0498] In a further development of this variant, only one of the inductors (the second inductor 309, the further inductor 311 or the yet further inductors, if provided) is of variable inductance, for example the second inductor 309. Nevertheless, by suitable choice of the (maximum) inductance of the second inductor 309 and of the inductance of the further inductor 311 and, if provided, the yet further inductors, the total inductance of the resonant circuit can be adjustable over a relatively wide range, in particular in small steps or (substantially) continuously. In this further development, each of the (yet) further inductors is provided with associated bypass circuitry. The second inductor 309 of variable inductance may or may not be provided with associated bypass circuitry. If the inductances of the second inductor (L2) and of the further inductors (L3, L4, L5, L6 etc.) are chosen according to a ratio of 1:1:2:4:8 etc., the lowest value of total inductance of the resonant circuit can be achieved if the third inductor (of inductance L3) and any further inductors (of inductance L4, L5, L6 etc.) are bypassed and the variable inductance (L2) of the second inductor 309 is adjusted to a minimum value L2min. Then, by adjusting the variable inductance L2 of the second inductor 309 over its adjustable range to a maximum value L2max, the total inductance of the resonant circuit can be adjusted from L1+L2min to L1+L2max (with L1 being the inductance of the first inductor 2). If (only) the third inductor is not bypassed (and the fourth and any further inductors are bypassed), the total inductance of the resonant circuit can be adjusted from L1+L3+L2min to L1+L3+L2max by adjusting the variable inductance L2 of the second inductor 309 over its adjustable range. If (only) the fourth inductor is not bypassed (and the third, fifth and any further inductors are bypassed), the total inductance of the resonant circuit can be adjusted from L1+L4+L2min to L1+L4+L2max. The next adjustable range of the total inductance can be achieved by not bypassing the third and fourth inductor and bypassing the fifth and any further inductors, and so on. If the relative inductances of the second inductor 309 and of the further inductors are chosen according to the above ratio, and further assuming that the variable inductance L2 of the second inductor 309 can be adjusted down to substantially zero (L2min=0), the total inductance of the resonant circuit can be adjusted (in discrete steps or substantially continuously) from substantially L1 to a maximum total inductance corresponding to the sum of all inductances of the resonant circuit, i.e. L1+L2max+L3+L4+L5 etc.

[0499] According to a further variant, which can be based on any of the embodiments explained with reference to FIGS. 8 to 10 or their variants, further inductors (together with any associated bypass circuitry, if applicable) may additionally be included in the first branch 5 or the second branch 6, as explained with reference to FIGS. 2 to 4 or their variants.

[0500] FIG. 11 schematically shows an apparatus for generating a magnetic field in accordance with an embodiment of the present disclosure. This is closely based on the embodiment shown in FIG. 9. However, the charging circuit shown in FIG. 9 is not shown in FIG. 11. Instead, FIG. 11 shows the capacitor 1 and the first and second branches 5 and 6 incorporated in a housing or cabinet 16 (electrically insulated from electric components and circuitry accommodated by cabinet 16). A terminal 19 for connection to an external charging circuit is provided on the cabinet 16 for the purpose of charging the capacitor 1. In a variant, the charging circuit, for example as shown in FIG. 9, can also be incorporated in the cabinet 16.

[0501] Cabinet 16 is provided with two further terminals, 17 and 18. Terminal 17 is connected to the second inductor 309 (and its associated bypass circuitry) and, therethrough, also to first branch 5 and second branch 6, whereas terminal 18 is connected to a common ground potential. In the embodiment shown in FIG. 11, terminal 18 is connected to the ground connection for the capacitor 1 via a line running within the cabinet 16.

[0502] FIG. 11 shows the first inductor 2 as a separate entity from cabinet 16 and its contents. The first inductor 2 is accommodated in a casing 13, which is attached to a conduit 14. Conduit 14 accommodates a cable 15, which is electrically connected to the first inductor 2, in particular to at least one set of turns of inductor 2, and which can be connected to the terminal 17 as indicated by a dashed line. In the embodiment shown in FIG. 11, the inductor 2 can also be connected, via a second cable, to the ground terminal 18 on cabinet 16.

[0503] As a variant of the embodiment shown in FIG. 11, the first inductor 2 could be connected to a ground potential via a separate line, i.e. not via the cabinet 16. In this case, the ground terminal 18 and the internal connection to ground could be omitted.

[0504] In further variants, features of the embodiment shown in FIG. 11 can be combined with features of the embodiments shown in FIGS. 8 and 10 or any variants described herein. Further, in any of the above embodiments or variants, any or all connections to ground could be omitted and replaced by an electrical connection between the different portions of the circuit. For example, in FIG. 8, the three connections to ground (triangles towards the bottom of the figure) could be replaced by an interconnection so that the (in FIG. 8 lower side of) capacitor 1, first inductor 2 and voltage source 7 are electrically connected.

[0505] In any of the above embodiments or variants, the polarities of the individual components can be reversed so that, for example, the negative terminal of the voltage source 7 is connected, via the switching device 8, to the first branch 5, second branch 6 and capacitor 1. The polarities of the thyristor 3 and the diode 4 would then also be reversed. Further, as has already been mentioned, the inventor has appreciated that the components and interconnections described in connection with the present invention are not “ideal” in the electrical sense. Enabled by the present disclosure, one skilled in the art will be able to make appropriate adjustments to allow for this. This applies in particular, but not exclusively, to the variant described above in which inductors having inductances according to a ratio of 1:1:2:4:8 etc. can be used. Appropriate adjustments can be made so as to take parasitic inductances into account, for example.

[0506] In further variants of the embodiments shown in FIGS. 8 to 11 or their variants described above, the position (in the electrical sense) of the second inductor 309 (along with any associated bypass circuitry 310) and of the parallel connection comprising the first branch 5 and the second branch 6 can be reversed so that the second inductor 309 is connected between capacitor 1 and the parallel connection comprising the first branch 5 and the second branch 6. This may also apply to any further inductors. What matters, according to such variants, is that the capacitor 1, the parallel connection comprising the first branch 5 and the second branch 6, the first inductor 2, the second inductor 309 and any further inductors (such as inductor 311) are connected in series.

[0507] FIG. 12 shows a flowchart illustrating a method in accordance with an embodiment of the present disclosure. After the start 390 of the method, any one of the apparatuses described above with reference to FIGS. 8 to 11 or their variants is provided (391). Electrical energy is then (392) stored in the electric storage device, in particular the capacitor 1. Thereafter, the switching device 3, in particular the thyristor 3, is switched (393) into a conductive or “ON” state so as to electrically connect the electric storage device 1 to the first inductor 2. This enables electrical current to flow through the first branch 5 and through the second inductor 309 (if not bypassed), through the first inductor 2 and, if applicable, through any further inductors such as further inductor 311 (if not bypassed), caused by the electrical energy stored by the electric storage device 1, thereby causing the first inductor 2 to generate a magnetic field. This current flow may represent a first half pulse or half wave. At the end of the first half pulse or half wave, electrical current is then enabled (394) to flow between the electric storage device 1 and the first inductor 2 through the second branch 6 via the electric component or assembly of electric components 4 (as well as via the second and any further inductors 309, 311, if not bypassed). This current flow may represent a second half pulse or half wave. At the end of the second half pulse or half wave, the method may end (395). Alternatively, the method or part thereof may be repeated. In particular, the switching device or thyristor 3 can again be switched (393) into the conductive or “ON” state etc. Electrical energy may also again be stored (392) in the electric storage device 1. In particular, the capacitor 1 may be recharged to its initial charging state, e.g. to compensate for dissipation of electrical energy in the apparatus.

[0508] FIG. 13 shows a diagram in which the current through the first inductor 2 is plotted over time, in accordance with an embodiment of the present disclosure. A circuit which might result in the diagram of FIG. 13 could be the circuit shown in FIG. 9, whereby the further switching device 310 is initially open, i.e. during the first half pulse (so that current flowing through the first inductor 2 will also flow through the second inductor 309). At the end of the first half pulse, the further switching device 310 is closed so as to short-circuit or bypass the second inductor 309. The first half pulse shown in FIG. 13 exhibits a slower rise and fall of the current through the first inductor 2 than the second half pulse. This is due to the higher total inductance during the first half pulse (total inductance=inductance of first inductor 2+inductance of second inductor 309) when compared with the total inductance during the second half pulse (total inductance=inductance of first inductor 2).

[0509] FIG. 14 schematically shows a circuit diagram of an apparatus for generating a magnetic field in accordance with an embodiment of the present disclosure. The circuit diagram shown in FIG. 14 is similar to that shown in FIG. 2. The above explanations regarding the device shown in FIG. 2 therefore also apply to the circuit diagram shown in FIG. 14 and will not be repeated here. Where elements shown in FIG. 14 have substantially the same function as elements shown in FIG. 2, these carry the same reference signs as in FIG. 2. Where elements shown in FIG. 14 are generally similar to elements shown in FIG. 2 but are different, for example in terms of their function or position within the circuit, these carry the reference signs as in FIG. 2 but increased by 400.

[0510] In contrast to the embodiment shown in FIG. 2, the second branch 6 does not include an additional inductor which does not (also) form part of the first branch 5. Instead, the circuit shown in FIG. 14 includes a capacitor 401 of variable capacitance—at the same position within the circuit where FIG. 2 has a capacitor 1 (which capacitor 1, in FIG. 2, is not specified as having a variable capacitance).

[0511] Capacitor 401 can in principle be any type of capacitor with a variable capacitance (or in short: a variable capacitor). The symbol used in FIG. 14 for capacitor 401 may typically be used for one particular type of variable capacitor only, but it is to be understood that this symbol is intended to represent any type of variable capacitor, including mechanically controlled variable capacitors and electrically controlled variable capacitors.

[0512] Whilst capacitor 401 is a single capacitor, it can nevertheless be regarded as a capacitor arrangement 420. Further examples of capacitor arrangements comprising several capacitors will be explained with reference to FIGS. 15 to 18.

[0513] When the capacitance of capacitor 401 of FIG. 14 is varied, this varies the resonant frequency of the resonant circuit of which capacitor 401 forms a part, i.e. the resonant circuit comprising capacitor 401, (first) inductor 2 and connecting circuitry (branches 5 and/or 6) connecting these. Accordingly, if the circuit of FIG. 14 is operated in a pulsed manner, the pulse duration is varied as well.

[0514] FIG. 15 schematically shows a circuit diagram of an apparatus for generating a magnetic field in accordance with an embodiment of the present disclosure. The embodiment shown in FIG. 15 is similar to that shown in FIG. 14, and the same explanations provided in connection with FIG. 14 also apply to the embodiment shown in FIG. 15. Like components carry like reference signs. FIG. 15 additionally shows a further capacitor 421 connected in parallel to capacitor 401. Accordingly, the capacitor arrangement 420 of FIG. 15 comprises the capacitors 401 and 421. The (total) capacitance of capacitor arrangement 420 of FIG. 15 corresponds (or is similar) to the sum of the (individual) capacitances of capacitors 401 and 421.

[0515] Capacitor 421 is shown as a variable capacitor, and the comments above regarding the symbol used for capacitor 401 also apply to capacitor 421. However, the further capacitor 421 does not necessarily need to have a variable capacitance—it could also have a fixed capacitance.

[0516] Varying the capacitance of capacitor 401 and/or capacitor 421 will vary the total capacitance of capacitor arrangement 420 and hence the resonant frequency of the resonant circuit of which the capacitor arrangement 420 forms a part.

[0517] In variants of the embodiment shown in FIG. 15, further capacitors, in particular capacitors of variable capacitance, can additionally be provided and connected in parallel to capacitor 401.

[0518] FIG. 16 schematically shows a circuit diagram of an apparatus for generating a magnetic field in accordance with an embodiment of the present disclosure. The embodiment shown in FIG. 16 is similar to that shown in FIG. 15, and the same explanations provided in connection with FIG. 15 also apply to the embodiment shown in FIG. 16. Like components carry like reference signs. FIG. 16 additionally shows a further switch or switching device 422 connected in series with the further capacitor 421. The further switching device 422 selectively establishes or interrupts an electrical connection between further capacitor 421 and capacitor 401. When the further switching device 422 is closed (or conductive), the further capacitor 421 is connected in parallel to capacitor 401 and the (total) capacitance of capacitor arrangement 420 of FIG. 16 corresponds (or is similar) to the sum of the (individual) capacitances of capacitors 401 and 421. When the further switching device 422 is open (or non-conductive), the (total) capacitance of capacitor arrangement 420 of FIG. 16 corresponds (or is similar) to the (individual) capacitance of capacitor 401—as if the further capacitor 421 was not present. In this way, by opening or closing the further switching device 422 (or selectively causing it to be non-conductive or conductive), the resonant frequency of the resonant circuit of which the capacitor arrangement 420 forms a part can be varied.

[0519] In this embodiment, the further capacitor 421 may have a fixed capacitance (as shown) or may alternatively have a variable capacitance. Further, in a variant, the position of the further capacitor and the further switching device 422 within the circuit is swapped so that the further switching device 422 is placed between the further capacitor 421 and ground. Electrically, this makes no significant difference and therefore this variant will be considered to be equivalent to the embodiment shown in FIG. 16.

[0520] In the embodiment of FIG. 16, if the (maximum) capacitance of capacitor 401 and the (maximum) capacitance of the further capacitor 421 are chosen to be the same, then the total capacitance of the capacitor arrangement 420 can be varied over a range from the minimum capacitance of capacitor 401 up to the sum of the (maximum) capacitances of capacitors 401 and 421. For example, if capacitor 401 can be adjusted between 0 μF and 100 μF and capacitor 421 has a (fixed) capacitance of 100 μF, then the total capacitance of the capacitor arrangement 420 can be varied between 0 μF and 100 μF when switching device 422 is open (or non-conductive) and between 100 μF and 200 μF when switching device 422 is closed (or conductive). If capacitor 401 is continuously variable between 0 μF and 100 μF, then the total capacitance of the capacitor arrangement 420 of this example can be varied continuously between 0 μF and 200 μF.

[0521] In another example, if capacitor 401 can be adjusted between 0 μF and 100 μF and capacitor 421 has a (fixed) capacitance of 300 μF, then the total capacitance of the capacitor arrangement 420 can be varied between 0 μF and 100 μF when switching device 422 is open (or non-conductive) and between 300 μF and 400 μF when switching device 422 is closed (or conductive).

[0522] FIG. 17 schematically shows a circuit diagram of an apparatus for generating a magnetic field in accordance with an embodiment of the present disclosure. The embodiment shown in FIG. 17 is similar to that shown in FIG. 16, and the same explanations provided in connection with FIG. 16 also apply to the embodiment shown in FIG. 17. Like components carry like reference signs. FIG. 17 additionally shows a (yet) further capacitor 423 connected in parallel to capacitor 401 (and in parallel to further capacitor 421). Accordingly, the capacitor arrangement 420 of FIG. 17 comprises the capacitors 401, 421 and 423. FIG. 17 also shows a (yet) further switch or switching device 424 connected in series with the further capacitor 423. The further switching device 424 selectively establishes or interrupts an electrical connection between further capacitor 423 and capacitor 401 (and further capacitor 421). When the further switching devices 422 and 424 are closed (or conductive), the further capacitors 421 and 423 are connected in parallel to capacitor 401 and the (total) capacitance of capacitor arrangement 420 of FIG. 17 corresponds (or is similar) to the sum of the (individual) capacitances of capacitors 401, 421 and 423. When the further switching devices 422 and 424 are open (or non-conductive), the (total) capacitance of capacitor arrangement 420 of FIG. 17 corresponds (or is similar) to the (individual) capacitance of capacitor 401—as if the further capacitors 421 and 423 were not present. The same applies, mutatis mutandis, if only one of the switching devices 422 and 424 is closed (or conductive) and the other is open (or non-conductive). In this way, by selectively opening or closing the further switching devices 422 and/or 424 (or selectively causing them to be non-conductive or conductive), the resonant frequency of the resonant circuit of which the capacitor arrangement 420 forms a part can be varied.

[0523] According to further variants, the capacitor arrangement 420 may be expanded by adding yet further capacitors and connecting these in parallel to capacitor 401. These yet further capacitors may have a variable capacitance or a fixed capacitance. In addition, yet further switching devices may be connected in series with yet further capacitors, similar to what is shown in FIG. 17.

[0524] In a further development of this variant, only one of the capacitors (the capacitor 401) is of variable capacitance—similar to what is shown in FIG. 17, but with yet further capacitors (and their associated yet further switching devices) connected in parallel to capacitor 401. Nevertheless, by suitable choice of the (maximum) capacitance of the capacitor 401 and of the capacitances of the further capacitors 421 and 423 and the yet further capacitors, the total capacitance of the capacitor arrangement and hence the total capacitance of the resonant circuit (and therefore also the resonant frequency of the resonant circuit) can be adjustable over a relatively wide range, in particular in small steps or (substantially) continuously. If the (maximum) capacitance C1 of the capacitor 401 and the capacitances C2, C3 of the further capacitors 421 and 423 and of the yet further capacitors (Cm, where m=4, 5, 6 . . . ) are chosen according to a ratio of 1:1:2:4:8 etc., the lowest value of total capacitance of the capacitor arrangement 420 can be achieved if all of the further switching devices 422, 424 and yet further switching devices are open or non-conductive and the variable capacitance C1 of the capacitor 401 is adjusted to a minimum value C1min. Then, by adjusting the variable capacitance C1 of the capacitor 401 over its adjustable range to a maximum value C1max, the total capacitance of the capacitor arrangement 420 can be adjusted from C1min to C1max. If (only) the further switching device 422 is closed or conductive (and all other (yet) further switching devices 424 etc. are open or non-conductive), the total capacitance of the capacitor arrangement 420 can be adjusted from C2+C1min to C2+C1max by adjusting the variable capacitance C1 of the capacitor 401 over its adjustable range. The next adjustable range of the total capacitance of the capacitor arrangement 420 can be achieved by further switching device 424 being closed or conductive and switching device 422 and all other yet further switching devices being open or non-conductive, and so on. If the relative capacitances are chosen according to the above ratio, and further assuming that the variable capacitance C1 of the capacitor 401 can be adjusted down to substantially zero (C1min=0 μF), the total capacitance of the capacitor arrangement 420 can be adjusted (in discrete steps or substantially continuously) from substantially 0 μF to a maximum total capacitance corresponding to the sum of all capacitances of the capacitor arrangement 420, i.e. C1max+C2+C3+C4 etc.

[0525] According to a further variant, which can be based on any of the embodiments explained with reference to FIGS. 14 to 17 or their variants, further inductors (together with any associated bypass circuitry, if applicable) may additionally be included in the first branch 5 or the second branch 6, as explained with reference to FIGS. 2 to 4 or their variants, and/or in series with the first inductor 2, as explained with reference to FIGS. 8 to 10 or their variants.

[0526] FIG. 18 schematically shows an apparatus for generating a magnetic field in accordance with an embodiment of the present disclosure. This is closely based on the embodiment shown in FIG. 17. However, the charging circuit shown in FIG. 17 is not shown in FIG. 18. Instead, FIG. 18 shows the capacitor arrangement 420 and the first and second branches 5 and 6 incorporated in a housing or cabinet 16 (electrically insulated from electric components and circuitry accommodated by cabinet 16). A terminal 19 for connection to an external charging circuit is provided on the cabinet 16 for the purpose of charging the capacitor arrangement 420. In a variant, the charging circuit, for example as shown in FIG. 17, can also be incorporated in the cabinet 16.

[0527] Cabinet 16 is provided with two further terminals, 17 and 18. Terminal 17 is connected to the first branch 5 and the second branch 6, whereas terminal 18 is connected to a common ground potential. In the embodiment shown in FIG. 18, terminal 18 is connected to the ground connection for the capacitor arrangement 420 via a line running within the cabinet 16.

[0528] FIG. 18 shows the first inductor 2 as a separate entity from cabinet 16 and its contents. The first inductor 2 is accommodated in a casing 13, which is attached to a conduit 14. Conduit 14 accommodates a cable 15, which is electrically connected to the first inductor 2, in particular to at least one set of turns of inductor 2, and which can be connected to the terminal 17 as indicated by a dashed line. In the embodiment shown in FIG. 18, the inductor 2 can also be connected, via a second cable, to the ground terminal 18 on cabinet 16.

[0529] As a variant of the embodiment shown in FIG. 18, the first inductor 2 could be connected to ground via a separate line, i.e. not via the cabinet 16. In this case, the ground terminal 18 and the internal connection to ground could be omitted.

[0530] In further variants, features of the embodiment shown in FIG. 18 can be combined with features of the embodiments shown in FIGS. 14 to 16 or any variants described herein. Further, in any of the above embodiments or variants, any or all connections to ground could be omitted and replaced by an electrical connection between the different portions of the circuit. For example, in FIGS. 14 to 17, the three connections to ground (triangles towards the bottom of the figures) could be replaced by an interconnection so that the (in FIGS. 14 to 17 lower side of the) capacitors of the capacitor arrangement 420, first inductor 2 and voltage source 7 are electrically connected.

[0531] In any of the above embodiments or variants, the polarities of the individual components can be reversed so that, for example, the negative terminal of the voltage source 7 is connected, via the switching device 8, to the first branch 5, second branch 6 and capacitor arrangement 420. The polarities of the thyristor 3 and the diode 4 would then also be reversed. Further, as has already been mentioned, the inventor has appreciated that the components and interconnections described in connection with the present invention are not “ideal” in the electrical sense. Enabled by the present disclosure, one skilled in the art will be able to make appropriate adjustments to allow for this. This applies in particular, but not exclusively, to the variant described above in which capacitors having capacitances according to a ratio of 1:1:2:4:8 etc. can be used. Appropriate adjustments can be made so as to take parasitic capacitances into account, for example.

[0532] FIG. 19 shows a flowchart illustrating a method in accordance with an embodiment of the present disclosure. After the start 490 of the method, any one of the apparatuses described above with reference to FIGS. 14 to 18 or their variants is provided (491). Electrical energy is then (492) stored in the capacitor arrangement 420, in particular the capacitor 401. Thereafter, the switching device 3, in particular the thyristor 3, is switched (493) into a conductive or “ON” state so as to electrically connect the capacitor arrangement 420 to the first inductor 2. This enables electrical current to flow through the first branch 5 and through the first inductor 2, caused by the electrical energy stored by the capacitor arrangement 420, thereby causing the first inductor 2 to generate a magnetic field. This current flow may represent a first half pulse or half wave. At the end of the first half pulse or half wave, electrical current is then enabled (494) to flow between the capacitor arrangement 420 and the first inductor 2 through the second branch 6 via the electric component or assembly of electric components 4. This current flow may represent a second half pulse or half wave. At the end of the second half pulse or half wave, the method may end (495). Alternatively, the method or part thereof may be repeated. In particular, the switching device or thyristor 3 can again be switched (493) into the conductive or “ON” state etc. Electrical energy may also again be stored (492) in the capacitor arrangement 420. In particular, the capacitor arrangement 420 may be recharged to its initial charging state, e.g. to compensate for dissipation of electrical energy in the apparatus.

[0533] As an optional, additional step (not shown in FIG. 19), the capacitance of the capacitor arrangement 420 can be varied, as explained above, either during the first or second half pulse or between the first and second half pulse or between a first (full) pulse and the next pulse.

[0534] FIG. 20 shows a diagram in which the current through the first inductor 2 is plotted over time, in accordance with an embodiment of the present disclosure. A circuit which might result in the diagram of FIG. 20 could be the circuit shown in FIG. 14, whereby the capacitance of the capacitor 401 is initially at a first capacitance value, i.e. during the first half pulse 430. The first half pulse 430 has a corresponding first duration. At the end of the first half pulse 430, the capacitance of the capacitor 401 is changed to a second capacitance value, which is lower than the first capacitance value. This increases the resonant frequency of the resonant circuit of which the capacitor 401 forms a part. Accordingly, the second half pulse 431 has a second duration, which is shorter than the first duration (of the first half pulse 430).

[0535] FIG. 21 schematically shows a circuit diagram of an apparatus for generating a magnetic field in accordance with an embodiment of the present disclosure. The circuit diagram shown in FIG. 21 is similar to that shown in FIG. 2 and other figures. The above explanations regarding the device shown in FIG. 2 (and other figures) therefore also apply to the circuit diagram shown in FIG. 21 and will not be repeated here. Where elements shown in FIG. 21 have substantially the same function as elements shown in FIG. 2 and other figures, these carry the same reference signs as in FIG. 2 (and in other figures). Where elements shown in FIG. 21 are generally similar to elements shown in FIG. 2 but are different, for example in terms of their function or position within the circuit, these carry the reference signs as in FIG. 2 but increased by 500.

[0536] In contrast to the embodiment shown in FIG. 2, the second branch 6 of FIG. 21 does not include an additional inductor which does not (also) form part of the first branch 5. Further, whilst the second branch 6 of the embodiment of FIG. 2 included an electric component 4 such as a diode, the embodiment of FIG. 21 includes a spark gap 542 and a resistor 543 (connected in series with the spark gap 542) in the second branch. In addition, the switching device 3 is a type of switching device which can not only be switched on (or transferred from the non-conductive state to the conductive state) but also off (or transferred from the conductive state to the non-conductive state). To this end, a (first) controller 540 is provided. Switching device 3 is controlled by controller 540 such that switching device 3 can be switched on and off at desired points in time. In particular, switching device 3 can be switched off at a point in time which does not coincide with the end of a first half pulse (assuming that the circuit shown in FIG. 21 is operated in a pulsed manner). Switching device 3 may, for example, comprise an insulated-gate bipolar transistor (IGBT), a field-effect transistor (FET), a metal—oxide—semiconductor field-effect transistor (MOSFET) or a gate turn-off thyristor (GTO-thyristor). The controller 540 may comprise analog circuitry or a microcontroller.

[0537] The operation of the circuit shown in FIG. 21 will now be explained, by way of example, with further reference to FIG. 24, which shows a flowchart illustrating a method in accordance with an embodiment of the present disclosure. The operation can be as follows: After the start 590 of the method, an apparatus with a circuit corresponding to the circuit shown in FIG. 21 (or any variants described herein) is provided (591). Electrical energy is then stored (592) in the capacitor arrangement 420 — in FIG. 21 represented by capacitor 1. Thereafter, at a first point in time, the switching device 3 is switched (593), under the control of controller 540, into a conductive or “ON” state so as to electrically connect the capacitor arrangement 420 to the inductor 2. This enables electrical current to flow through the first branch 5 and through the inductor 2, caused by the electrical energy stored by the capacitor arrangement 420, thereby causing the inductor 2 to generate a magnetic field. This current flow may represent a first half pulse or half wave. However, the current flow may be interrupted at a selected second point in time. To this end, the switching device 3 is switched (594), under the control of controller 540, into the non-conductive or “OFF” state so as to electrically disconnect the capacitor arrangement 420 from the inductor 2. The second point in time can, for example, be during the first half pulse.

[0538] With the switching device 3 in the non-conductive state, electrical current can no longer flow through the switching device 3. However, the magnetic field, which has already been generated (by inductor 2), will resist its decay, which means that electrical current will continue to flow through inductor 2, resulting in a (relatively high) voltage in the first and second branch 5, 6. Eventually, this voltage is high enough to cause the spark gap 542 to become conductive (595), thereby enabling electrical current to flow between the capacitor arrangement 420 and the inductor 2 through the second branch 6 via resistor 543 and spark gap 542. The energy that was stored in the magnetic field is then at least partially dissipated in resistor 543. The method may then end (596). Alternatively, the method or part thereof may be repeated. In particular, the switching device 3 can again be switched (593) into the conductive or “ON” state etc. Electrical energy may also again be stored (592) in the capacitor arrangement 420. In particular, the capacitor arrangement 420 may be recharged to its initial charging state, e.g. to compensate for dissipation of electrical energy in the apparatus.

[0539] As per the above description with reference to FIGS. 21 and 24, the spark gap 542 may protect switching device 3 from damage or destruction, in particular if spark gap 542 is constructed such that it becomes conductive at a voltage U2, which is lower than a voltage U3 at which switching device 3 would suffer damage or be destroyed. On the other hand, spark gap 542 should not already become conductive at a voltage U1 to which the capacitor arrangement 420 is (to be) charged.

[0540] In variants (not specifically illustrated), other electrical circuit elements (some of which are normally classified as passive circuit elements) can be used instead of a spark gap 542, in particular a transient-voltage-suppression diode, a Zener diode, a Shockley diode, a triode for alternating current (TRIAC) or a thyristor, in particular in combination with trigger circuitry connected to, or forming part of, the second branch to trigger the thyristor.

[0541] FIG. 22 illustrates a variant of the embodiment of FIG. 21. Instead of a spark gap 542, an active electrical circuit element 503 or an arrangement of circuit elements is included in the second branch 6, in particular a switching element 503 controlled by analog circuitry or a microcontroller (or controlled by a second controller 541 comprising analog circuitry or a microcontroller). Using controller 541, a user can actively control the electrical circuit element 503, rather than the electrical circuit element 503 simply being allowed to become conductive or non-conductive depending on the voltage applied to its two terminals within the second branch 6.

[0542] FIG. 23 illustrates a further development of the embodiment of FIG. 22. In the embodiment of FIG. 23, the apparatus comprises a control unit 544 for controlling the first controller 540 and the second controller 541. To this end, the control unit 544 is connected to the first and the second controller 540, 541 (indicated by dashed lines). In this way, any, some or all of the points in time at which the switching device 3 and/or the switching element 503 are to be switched from the non-conductive state to the conductive state and vice versa can be controlled via control unit 544. In particular, the first and/or second points in time for switching the switching device 3 on and off can be selected via control unit 544. Similarly, third and/or fourth points in time for switching the switching element 503 on and off can be selected via control unit 544.

[0543] In order to enable a user to select any of the first to fourth points in time, the control unit 544 may have one or more dials 545 and/or any other (user) interface, such as a touchscreen 546. Control unit 544 may further comprise a processor/memory 547.

[0544] In a variant (not specifically illustrated), control unit 544 is connected directly to switching device 3 and/or switching element 503 in order to control these, in which case controllers 540 and/or 541 can be omitted.

[0545] In a further variant (not specifically illustrated), the apparatus may further have one or more detectors for taking measurements at one or more places within the circuit shown in FIG. 23, such as a voltage between the terminals of switching device 3 in the first branch 5 and/or a voltage between the terminals of switching element 503 in the second branch 6. These measurements can be communicated to control unit 544. Depending on the measurements taken, the control unit 544 can set any of the first to fourth points in time, for example in order to protect any elements of the circuit from damage or destruction, such as switching device 3 and/or switching element 503.

[0546] FIG. 23 shows a further development of the circuit. This further development involves a detector 548. Detector 548 is intended to detect a neural reaction or a cellular physiological reaction, in particular a muscle reaction, in body tissue—represented by a human arm 551 in FIG. 23, although detector 548 can be used in connection with any other body part of a human or animal. Detector 548 is also connected to control unit 544, as indicated by a dashed line. The operation of this further development will be explained with further reference to FIG. 25.

[0547] FIG. 25 shows several curves, in which current (I) through inductor 2 is plotted over time (t). Curve 549 follows the shape of a sine function and represents the current through inductor 102 of FIG. 1 under ideal conditions during a first half pulse. This therefore also represents the current through inductor 2 of FIG. 23 if switching device 3 was not switched into the non-conductive state during the first half pulse (i.e. if the second point in time was not before the end of the first half pulse).

[0548] When inductor 2 is applied to body tissue 551, the magnetic field generated by inductor 2 causes a current in the body tissue, as has been explained above. This current within the body tissue at least approximately follows the same shape as the current through inductor 2, albeit at a (significantly) reduced level and shifted in phase. The current within the body tissue can therefore be regarded as (approximately) proportional to the current through inductor 2 (but shifted in phase).

[0549] FIG. 25 shows four additional curves, 550a to 550d. These indicate the current through inductor 2 in cases where switching device 3 is switched into the non-conductive state before the end of the first half pulse, respectively at “second points in time” t1 to t4. The “first point in time” corresponds to the origin of the graph. In each case, the switching of switching device 3 into the non-conductive state results in a relatively steep drop in the current. That is, initially the current through inductor 2—after the first point in time (i.e. the origin), when switching device 3 is switched into the conductive state—follows the sine shape 549. After the “second points in time” t1 to t4, the current respectively continues along curves 550a to 550d. These further curves 550a to 550d therefore represent different scenarios, depending on when the switching device 3 is switched into the non-conductive state.

[0550] In the cases of curves 550a to 550c, the current reaches a maximum of I1 to 13, respectively. By varying the second point in time, in particular within the first quarter pulse (i.e. up to the time corresponding to the maximum of the sine shape 549), the maximum current that will be reached (through inductor 2 and also within the body tissue) can also be varied.

[0551] As mentioned, detector 548 is intended to detect a neural reaction or a cellular physiological reaction, in particular a muscle reaction in body tissue. If the current within the body tissue is sufficiently low, detector 548 will not detect any neural reaction or cellular physiological reaction, in particular a muscle reaction. In view of the graph shown in FIG. 25, this would correspond to a situation where the time interval between the first point in time (the origin) and the second point in time (e.g. t1) is very short. By increasing the time interval, the current within the body tissue will also increase, and eventually a neural reaction or a cellular physiological reaction, in particular a muscle reaction, will be detected by detector 548. For example, a neural reaction or cellular physiological reaction (but not a muscle reaction) might be detected if the time interval ends at t2, and a muscle reaction will be detected if the time interval ends at t3.

[0552] The detection result, i.e. whether a neural reaction or a cellular physiological reaction, in particular a muscle reaction, has been detected by detector 548 can be transmitted from detector 548 to control unit 544, in particular to processor/memory 547. Processor/memory 547 can process this information, as well as the information regarding the applicable time interval (or the second point in time) in order to determine the (shortest) time interval at which a neural reaction or cellular physiological reaction, in particular a muscle reaction, can be detected.

[0553] Curve 550d is less useful for determining the (shortest) time interval at which a neural reaction or cellular physiological reaction, in particular a muscle reaction, can be detected, since t4 is in the second quarter pulse, i.e. the maximum current (according to the sine function 549) has already been reached before t4.

[0554] In further variants, features of the embodiments shown in FIGS. 21 to 23 can be combined with features of the embodiments shown in FIGS. 2 to 4, 8 to 10, 14 to 17 or any variants described herein. Further, any of the above embodiments or variants can be adapted in a manner similar to what is shown in, and described in connection with, FIGS. 5, 11 and 18—in particular providing an apparatus according to FIGS. 21 to 23, but providing this apparatus with terminals 17, 18 and/or 19, for connection with an inductor 2 and/or an external charging circuit, respectively.

[0555] In any of the above embodiments or variants, the polarities of the individual components can be reversed so that, for example, the negative terminal of the voltage source 7 is connected, via the switching device 8, to the first branch 5, second branch 6 and capacitor arrangement 420.

[0556] FIG. 26 schematically shows a circuit diagram of an apparatus for generating a magnetic field in accordance with an embodiment of the present invention. The circuit diagram shown in FIG. 26 is similar to that shown in FIG. 2. The above explanations regarding the device shown in FIG. 2 therefore also apply to the circuit diagram shown in FIG. 26 and will not be repeated here. Where elements shown in FIG. 26 have substantially the same function as elements shown in FIG. 2, these carry the same reference signs as in FIG. 2. Where elements shown in FIG. 26 are generally similar to elements shown in FIG. 2 but are different, for example in terms of their function or position within the circuit, these carry the reference signs as in FIG. 2 but increased by 600.

[0557] In contrast to the embodiment shown in FIG. 2, the first inductor 2 is connected to, or forms part of, the first branch 5, but not the second branch 6. Similarly, a second inductor 609 is provided, which is connected to, or forms part of, the second branch 6, but not the first branch 5. The two branches 5, 6 are effectively separate, except that both are connected to the electric storage device 1 (again represented by a capacitor 1) and that they are both connected to a common ground potential (small triangles towards the bottom of the figure).

[0558] The first branch 5 also includes a switching device 3, and the above explanations as to possible types of switching devices also apply to the embodiment of FIG. 26. The second branch 6 also includes a switching device 603, and the above explanations as to possible types of switching devices also apply to switching device 603. The first and second switching devices 3, 603 may be of the same type, or may be of different types. In FIG. 26, the first switching device 3 and the second switching device 603 are shown as thyristors, by way of example. The polarity of the first switching device 3 is such that it allows current to flow substantially in only one direction, this representing a first current direction of current flow with respect to the electric storage device 1. The polarity of the second switching device 603 is such that it allows current to flow substantially in only one direction, this representing a second current direction of current flow with respect to the electric storage device 1. The second current direction of current flow with respect to the electric storage device 1 is opposite the first current direction.

[0559] The operation of the circuit shown in FIG. 26 will now be described, by way of example, with further reference to FIGS. 30 and 31. FIG. 30 shows a graph in which the current (I) through the first inductor 2 and the second inductor 609 is plotted over time (t). The graph of FIG. 30 can also be regarded as the current between the electric storage device 1 and the point where the first and second branches 5, 6 are connected. FIG. 31 shows a flowchart illustrating a method in accordance with an embodiment of the present invention. The operation can be as follows. After the start 690 of the method, an apparatus with a circuit corresponding to the circuit shown in FIG. 26 (or any variants described herein) is provided (691). Electrical energy is then stored (692) in the electric storage device 1. Thereafter, at a first point in time t1, the switching device 3 is switched (693) into a conductive or “ON” state, for example under the control of a suitable controller (such as a controller described herein in connection with other embodiments), so as to electrically connect the electric storage device 1 to the first inductor 2. This enables electrical current to flow through the first branch 5 and through the first inductor 2, caused by the electrical energy stored by the electric storage device 1, thereby causing the first inductor 2 to generate a first magnetic field. This current flow may represent a first half pulse or half wave 620.

[0560] At the end of the first half pulse 620, i.e. at a second point in time t2, the first magnetic field generated by first inductor 2 has essentially reduced to zero, and the electric storage device 1 has now reached its maximum charge, however of opposite polarity when compared with the initial state (just before t1). The absolute value of this maximum charge at t2 may be somewhat lower than the absolute value of the initial maximum charge (just before t1).

[0561] At a third point in time t3, the switching device 603 is switched (694) into a conductive or “ON” state, for example under the control of a suitable controller (such as a controller described herein in connection with other embodiments), so as to electrically connect the electric storage device 1 to the second inductor 609. This enables electrical current to flow through the second branch 6 and through the second inductor 609, caused by the electrical energy stored by the electric storage device 1, thereby causing the second inductor 609 to generate a second magnetic field. This current flow may represent a second half pulse or half wave 630.

[0562] At the end of the second half pulse 630, i.e. at a fourth point in time t4, the second magnetic field generated by second inductor 609 has essentially reduced to zero, and the electric storage device 1 has now reached its maximum charge, of the same polarity as during the initial state just before t1 (albeit at a somewhat reduced level, assuming that some losses of energy have occurred in the apparatus between t1 and t4). The method may then end (695). Alternatively, the method or part thereof may be repeated. In particular, the first switching device 3 can again be switched (693) into the conductive or “ON” state etc. Electrical energy may also again be stored (692) in the electric storage device 1. In particular, the capacitor 1 may be recharged to its initial charging state, e.g. to compensate for dissipation of electrical energy in the apparatus.

[0563] As will be appreciated from the above description, the two half pulses 620, 630 shown in FIG. 30 relate to different inductors, 2 and 609, respectively. While current flows through the first inductor 2 between t1 and t2, (substantially) no current flows through the second inductor 609. While current flows through the second inductor 609 between t3 and t4, (substantially) no current flows through the first inductor 2. Further, it will be appreciated from FIG. 30 and the above description that the delay between t2 and t3 can be chosen, in particular substantially freely, in particular by a user or manufacturer. In particular, the delay between t2 and t3 may be longer or shorter than the time interval between t1 and t2, or may be of the same duration. The two points in time t2 and t3 may also be selected such that they (substantially) coincide.

[0564] As will also be appreciated, the first and second inductances respectively of the first and second inductors 2, 609 may or may not be the same. In the example of FIG. 30, the second inductance of the second inductor 609 is smaller than the first inductance of the first inductor 2. Accordingly, the time between t3 and t4 is shorter than the time between t1 and t2.

[0565] FIG. 27 schematically shows an apparatus for generating a magnetic field in accordance with an embodiment of the present invention. This is closely based on the embodiment shown in FIG. 26. FIG. 27 shows the capacitor 1, the charging circuit comprising a source of electrical energy 7 and a switching device 8, as well as (a portion of) first and second branches 5 and 6 with first and second switching devices 3, 603 incorporated in a housing or cabinet 16 (electrically insulated from electric components and circuitry accommodated by cabinet 16). First inductor 2 is accommodated in a first casing 13. Second inductor 609 is accommodated in a second casing 613. The first casing 13 is movable independently from the second casing 613. Both are also movable with respect to cabinet 16 and may be electrically connected to the remainder of the circuit by flexible cables.

[0566] FIG. 28 schematically shows an apparatus for generating a magnetic field in accordance with an embodiment of the present invention. This is closely based on the embodiment shown in FIG. 27. However, in contrast to the embodiment of FIG. 27, both inductors 2, 609 are accommodated in the same casing 13 and are therefore not movable with respect to one another. The casing 13 may be movable with respect to cabinet 16. The first and second inductors 2, 609 may again be electrically connected to the remainder of the circuit by flexible cables. The cables may, for example, be arranged in a single conduit (not shown).

[0567] FIG. 29 schematically shows an apparatus for generating a magnetic field in accordance with an embodiment of the present invention. This is closely based on the embodiment shown in FIG. 28. However, in contrast to the embodiment of FIG. 28, the first and second inductors 2, 609, as well as the casing 13 in which they are accommodated, are provided as a separate unit for connection to cabinet 16. To this end, cabinet 16 is provided with a number of terminals. In the example shown in FIG. 29, there are four such terminals: terminals 17, 18 for electrical connection to first inductor 2, and terminals 617, 618 for electrical connection to second inductor 609. Depending on the construction of the first and second inductors 2, 609 and any cable(s) 15 connecting the first and second inductors 2, 609 to the remainder of the circuit, a different number of terminals may be provided on the cabinet 16. FIG. 29 also shows a conduit 14 in which the cables 15 may be arranged.

[0568] Within cabinet 16, terminal 17 is connected to the first switching device 3, and terminal 18 is connected to the ground connection for the capacitor 1 via a line running within cabinet 16. Similarly, terminal 617 is connected to the second switching device 603, and terminal 618 is again connected to the ground connection for the capacitor 1.

[0569] Whilst FIG. 29 shows the first and second inductors 2, 609 accommodated in the same casing 13, they may also be accommodated in separate casings and may be movable with respect to one another, similar to the embodiment of FIG. 27.

[0570] In variants of the embodiments of FIGS. 27 to 29, the charging circuit (comprising the source of electrical energy 7 and the switching device 8) or portions thereof may be provided separately (i.e. not within cabinet 16), for example as shown in FIGS. 5, 11 and 18, in which case cabinet 16 is provided with a further terminal 19 for connection to the external charging circuit.

[0571] In further variants, features of the embodiments shown in FIGS. 26 to 29 can be combined with features of the embodiments shown in FIGS. 2 to 5, 8 to 11, 14 to 18 and 21 to 23 or any variants described herein.

[0572] In any of the above embodiments or variants, the polarities of the individual components can be reversed so that, for example, the negative terminal of the voltage source 7 is connected, via the switching device 8, to the first branch 5 and the second branch 6. The polarities of the switching devices 3, 603 could then also be reversed—or they could remain the same, in which case the two branches 5, 6 and the two inductors 2, 609 swap their functions.

[0573] While at least one example embodiment of the present invention has been described above, it has to be noted that a great number of variations thereto exist. Furthermore, it is to be appreciated that the described example embodiments only illustrate non-limiting examples of how the present invention can be implemented and that it is not intended to limit the scope, the application or the configuration of the apparatuses and methods described herein. Rather, the preceding description will provide the person skilled in the art with instructions for implementing at least one example embodiment of the invention, whereby it has to be understood that various changes in the functionality and the arrangement of the elements of the example embodiment can be made without deviating from the subject-matter defined by the appended claims and their legal equivalents.

LIST OF REFERENCE SIGNS

[0574] 1 electric storage device, capacitor

[0575] 2 first inductor, set of turns

[0576] 3 switching device, thyristor

[0577] 4 electric component or assembly of electric components, diode

[0578] 5 first branch (of connecting circuitry)

[0579] 6 second branch (of connecting circuitry)

[0580] 7 source of electrical energy, voltage source

[0581] 8 switch, switching device, switching circuitry

[0582] 9 second inductor

[0583] 10 bypass circuitry

[0584] 11 further inductor

[0585] 12 further bypass circuitry

[0586] 13 casing

[0587] 14 conduit

[0588] 15 cable

[0589] 16 housing, cabinet

[0590] 17-19 terminals

[0591] 90-95 method steps

[0592] 101 capacitor

[0593] 102 inductor

[0594] 103 thyristor

[0595] 104 diode

[0596] 105 first branch

[0597] 106 second branch

[0598] 107 voltage source

[0599] 108 switch

[0600] 200 first half pulse

[0601] 210 second half pulse

[0602] 309 second inductor

[0603] 310 bypass circuitry

[0604] 311 further inductor

[0605] 312 further bypass circuitry

[0606] 320 first half pulse

[0607] 330 second half pulse

[0608] 390-395 method steps

[0609] 401 (first) variable capacitor

[0610] 420 capacitor arrangement

[0611] 421, 423 further capacitor (optionally: variable)

[0612] 422, 424 further switching devices

[0613] 430 first half pulse

[0614] 431 second half pulse

[0615] 490-495 method steps

[0616] 503 switching device

[0617] 540 (first) controller

[0618] 541 (second) controller

[0619] 542 spark gap

[0620] 543 resistor

[0621] 544 control unit

[0622] 545 dial/interface

[0623] 546 touch screen/interface

[0624] 547 processor/memory device

[0625] 548 detector

[0626] 549 electrical current (half pulse)

[0627] 550a-d electrical current

[0628] 551 body part

[0629] 590-596 method steps

[0630] 603 switching device, thyristor

[0631] 609 second inductor

[0632] 613 casing

[0633] 617, 618 terminals

[0634] 620 first half pulse

[0635] 630 second half pulse

[0636] 690-695 method steps