This shield circuit is from a 1968s Motorola documentation. The relay is according to the supply voltage. R1 can be reduced to lower trigger voltages.
What differentiates the CIR8139 circuit is the use of two inverter ports to trigger the transistor that...
The battery charger suggested in the figure has its current limited by resistor R1. This component may...
This circuit with increased power output was found in the November 1974 Radio Electronics...