A voltage controlled impedance synthesizer providing stepwise variable impedance values according to a prescribed function of the control voltage, said synthesizer comprises of one or more two-terminal impedance modules connected in series, in each impedance module one or more essentially identical two-terminal impedance elements connected in series, a corresponding number of switches to short out by selection none to all of the impedance elements in the impedance module, and said switches being controlled by the control voltage through analog-to-digital conversion and digital processing means. The values of the impedance elements between the impedance modules in ratios being uniquely defined according to the numbers of impedance elements in the impedance modules, the voltage controlled impedance synthesizer is controlled to provide monotonic and stepwise variable impedance values. Further, through the use of the voltage controlled impedance synthesizer, other electrical parameters such as current and power can be controlled according to any prescribed functions.

Control console for a powered surgical tool that includes a transformer with a secondary winding across which the tool drive signal is present. Also internal to the transformer is a matched current source that consists of a leakage control winding and a capacitor. The current sourced by the matched current at least partially cancels out leakage current that may be present.

Control console for a powered surgical tool that includes a transformer with a secondary winding across which the tool drive signal is present. Also internal to the transformer is a matched current source that consists of a leakage control winding and a capacitor. The current sourced by the matched current at least partially cancels out leakage current that may be present.

A filter device includes a first LC series resonator to resonate in series at a first series resonant frequency with a first inductor and a first capacitor, and a second LC series resonator to resonate in series at a second series resonant frequency with a second inductor and a second capacitor. The first and second LC series resonators are connected in parallel and resonate in parallel at a parallel resonant frequency. The second series resonant frequency is lower than the first series resonant frequency. The parallel resonant frequency is between the first and second series resonant frequencies.