One aspect of this disclosure relates to an apparatus for providing a selective capacitance. An embodiment of the apparatus includes a first and second capacitor in a stack, and a switching circuit connected between the first and second capacitors. The switching circuit has at least two states, and is adapted to provide a first defibrillation capacitance in a first state and a second defibrillation capacitance in a second state. A switching circuit embodiment includes a field effect transistor (FET) adapted to have a source connected to the first capacitor and a drain connected to the second capacitor, a bipolar junction transistor (BJT) adapted to have an emitter connected to the source of the FET and a collector connected to a gate of the FET, a first current source connected to the collector of the BJT, and a second current source connected to a base of the BJT.
