Capacitor slow charging control circuit - uses transistor base current for charging, with emitter circuit control

摘要

The capacitor charging circuit operates at a speed determined according to the product of resistance and capacitance values. The base current of an NPN transistor is used to charge the capacitor. The base current is controlled by a resistance in the emitter circuit of the emitter circuit of the control transistor. A second transistor in the emitter circuit of the control transistor may alternatively be used to regulate the charging rate. A total charging time of several seconds may be achieved and this may be used in a time control circuit.