Found on a 1969 EDN this circuit switches a current from a digital control signal. The impedance of the circuit ON is approximately 10 ohms. Modern equivalent transistors may be used.
Found in a 1967 Delco documentation, this circuit can deliver power from 40 to 50 W at 8-ohm load....
This Intersil circuit was found in a 1980s documentation. Operational are of the time, but current...
We found this circuit in a 1980s American publication from Motorola. Modern equivalent transistors...