This power stage with two transistors was found in Radio Electronics magazine from October 1963. The transistors must be equipped with heatsinks and the supply voltage is 12 V.
The circuit in the figure is based on an LM101A; diodes can be replaced with equivalents. The...
This circuit, with magnetic sensor, uses an operational amplifier of the time. The circuit is from...
Found in a 90s Popular Electronics, this circuit checks if a remote-control transmitter is...