the patient particularly to the patient 39 s heart the current level i is determined by ohm 39 s law as v 1 u2212 v 2 r patient this current thus flows to and charges c 2 causing its voltage to increase the boost configured switching circuitry comprised of l 1 q 1 d 1 and the control circuit extract energy from c 2 and u201c pump u201d or deliver it back into c 1 as c 1 discharges the control circuit also adjusts the switching action to maintain the voltage difference v 1 u2212 v 2 substantially constant and thus the current or electrotherapy pulse delivered to the patient is generally maintained at the desired level 0034 fig4 is a diagram of another preferred embodiment of the invention as before capacitor c 1 is the main energy storage element now comprised of four aluminum electrolytic capacitors c 1 a c 1 b c 1 c c 1 d connected in series typical preferred values would be about 800 uf for each capacitor and would each be charged to approximately 400 volts for a total voltage of 1600 switches s 1 and s 2 connect the patient to the defibrillator circuitry through electrodes e 1 and e 2 for purposes of illustration only it will be assumed that the patient impedance is 75 ohms also as before the secondary switched voltage source is comprised of capacitor c 2 inductor l 1 semiconductor switch q 1 diode d 1 and the control circuitry as well as resistors r 1 and r 2 the main storage capacitor c 1 is charged to 1600 volts by a high.