This circuit with TTL output was found in a 1968 EEE. The transistor can be of general use. The tunnel diode is an uncommon component today.
Incandescent lamps, heaters and other resistive loads can be controlled by this circuit whose...
The transistor of this constant current source may be the BC548 or equivalent. Resistor R2 may be...
This 300 kHz and 400 kHz two-channel transmitter for TV remote control appeared at Radio...