A transformer includes: a base that is a plate-like member and has a first surface and a second surface, a core attached to the first surface of the base, coils wound around the core, coil terminals attached to the second surface of the base, and a cooling unit that is thermally connected to the core and is to release heat transferred from the core. The coil terminals are disposed on the second surface of the base opposite to the first surface of the base to which the core is attached. The cooling unit is disposed on a side of the core opposite to the base.

An exemplary transformer is provided for high voltage and low leakage inductance, including an outer housing, a complementary pair of iron C-sections, bobbins and Litz wire. The iron C-sections form a magnetic loop core, forming proximal and distal sides. The bobbins include outer and inner primary bobbins, as well as outer, middle and inner secondary bobbins. The inner secondary bobbin has a center gap for receiving the proximal side of the core and is disposable within the inner primary bobbin. Inner and outer primary Litz wires have rectangular cross-sections and respectively wrap around the inner and outer primary bobbins. The secondary Litz wire contiguously wraps around the secondary bobbins. The primary Litz wires connect together by a shunt. The inner primary bobbin is disposable within the middle secondary bobbin. The middle secondary bobbin is disposable within the outer primary bobbin. The outer primary bobbin is disposable within the outer secondary bobbin. The outer secondary bobbin is disposable within the housing.

This DC power supply device comprises: a transformer having a primary magnetic core, a secondary magnetic core, at least one primary coil wound on the primary magnetic core, and a plurality of secondary coils wound on the secondary magnetic core; and at least one bridge composed of transistors. The DC power supply device has: a primary circuit connected to the primary coil; and a plurality of secondary circuits respectively connected to the plurality of secondary coils and each having a first secondary resonance capacitor, a second secondary resonance capacitor, and a smoothing circuit. The primary circuit and the plurality of secondary circuits are electrically insulated from each other by the transformer. In the plurality of secondary circuits, output parts of respective smoothing circuits are serially connected to each other. The primary magnetic core and the secondary magnetic core are disposed to face each other with an insulator disposed therebetween.

A circuit is operative to extract electromagnetic wave energy from the ground via a resonant transformer in which resonance is triggered by electrical charge arcing across a spark gap. A center tap of the primary winding of the transformer is capacitively coupled to an electrode buried in the ground. In-rush current from the ground electrode is converted to a useful form (e.g., one- or three-phase 60 Hz AC) by a power conversion circuit connected to the secondary winding of the resonant transformer. The ground electrode of the capacitor coupling the grounded electrode to the center tap primary winding is the shield of a Faraday cage enclosing the resonant transformer, spark gap, and a high-voltage power supply exciting the spark gap.

A coil component including: a terminal for external connection to which a plurality of secondary-side winding wires are connected; and a gathering member configured to gather vicinities of terminal ends of the plurality of winding wires.

A transformer includes a first iron core group, a second iron core group, and winding portions. The first iron core group includes iron core stacks. The second iron core group includes iron core stacks each disposed to face a corresponding one of the iron core stacks of the first iron core group. Each of the winding portions is wound around its corresponding iron core stack of the first iron core group and its corresponding iron core stack of the second iron core group, the corresponding one iron core stack of the second iron core group facing the corresponding one iron core stack of the first iron core group. The iron core stacks of the first iron core group and the iron core stacks of the second iron core group each include annular iron cores stacked alternately.

A switch-mode DC-DC power converter includes one or more input terminals and output terminals, and a transformer coupled between the input and output terminals. The transformer includes a plurality of winding sets. Each winding set includes a primary winding and a secondary winding magnetically coupled with one another. The primary winding and the secondary winding include the same number of turns. The primary windings of the plurality of winding sets are connected in series and the secondary windings of the plurality of winding sets are connected in parallel. The power converter also includes at least one spacer positioned to separate an adjacent pair of the plurality of winding sets. A magnetic coupling between the adjacent pair of the plurality of winding sets is less than the magnetic coupling between the primary winding and the secondary winding within each winding set.

A coil structure has a coil 150 including conductors, and insulating sheets 100 provided between the conductors included in the coil 150. Two or more insulating sheets 100 are provided. The two or more insulating sheets 100 have two or more types of insulating sheets 100 having at least different thermal conductivity or different permittivity.

A coil structure has a coil 150 including conductors, and insulating sheets 100 provided between the conductors included in the coil 150. Two or more insulating sheets 100 are provided. The two or more insulating sheets 100 have two or more types of insulating sheets 100 having at least different thermal conductivity or different permittivity.

A switch-mode DC-DC power converter includes one or more input terminals and output terminals, and a transformer coupled between the input and output terminals. The transformer includes a plurality of winding sets. Each winding set includes a primary winding and a secondary winding magnetically coupled with one another. The primary winding and the secondary winding include the same number of turns. The primary windings of the plurality of winding sets are connected in series and the secondary windings of the plurality of winding sets are connected in parallel. The power converter also includes at least one spacer positioned to separate an adjacent pair of the plurality of winding sets. A magnetic coupling between the adjacent pair of the plurality of winding sets is less than the magnetic coupling between the primary winding and the secondary winding within each winding set.