Capacitor is 2 conducting plates separated by an insulator which will store electrons (charge) when a potential difference applied (voltage).
Capacitance is the ability to hold charge and is measured in farads.
Blocks DC but passes AC current.

Diode converts mains AC to DC.
Capacitor stores charge.
Inductor lengthens the current pulse to optimum.
Energy released as single current pulse of 35 A for 3ms.
Monophasic – current travels in one direction only.
Can be either exponential current decay or damped sine wave – similar efficacy.
Current reversed halfway through discharge.
Either exponential or rectilinear.
More effective and causes less myocardial damage.