stated below when the voltage across terminals 35 and 37 becomes less positive than the voltage of the batteries 41a 41n or only one battery if only one is in circuit the battery or batteries commence to discharge into the terminal 35 of the tertiary winding no significant discharge current is expected to flow because of the blocking action of diode 38 however a small reverse current does flow from the battery or batteries 41a 41n because of the stored charge on the intrinsic capacitance of the diode 38 and or from the stored charge on the capacitor 42 if present to augment the intrinsic capacitance to repolarize the diode 38 after which no further discharge can take place this small reverse current flow into terminal 35 coupled with the collapse of voltage across the tertiary winding induces a positive voltage at terminal 27 of the transformer secondary winding 26 which again initiates regeneration and the cycle is repeated depending upon the characteristics of transformer 21 and the diode 38 it may be desirable to increase the battery discharge current which reinitiates an oscillation cycle such is the purpose of the capacitor 42 when the voltage at the terminal 35 is no longer sufficient to force charging current into the positive terminal of battery 41a and the batteries 41a 41n start to discharge current in addition to that required to repolarize the diode 38 will flow to repolarize the.