This old 1 W audio amplifier transistor circuit is from a 1967 Japanese magazine. The transistors are germanium of the time and the type transformers found in similar equipment of the time.
This simple circuit allows the monitoring of both audio and RF signals. With the switch in one...
This circuit was found in documentation from the 1980s. The integrated circuit used is uncommon today...
With a light pulse on the Q1 sensor the circuit turns on and locks. To switch off, a light pulse...