This 1980s circuit was found in Motorola documentation. The circuit uses period components that admit of equivalents. Light feedback in a modern version can be done by optical fiber.
This is the circuit of a small commercial amplifier from the 1970s from Philips Argentina. The...
Originally created to power an 80's RTTY printer, this circuit can be used in other applications. The...
This circuit was found in a 1968 Hughes documentation. The transistors are from that time. The coil...