Found in old American documentation, this receiver receives modulated infrared signals and converts them into sound. The audio amplifier circuit can be replaced by a modern equivalent.
This circuit triggers an alarm when the mains power is cut off. The circuit was found in the July...
This acutely tuned circuit was found in American documentation from the 1960s. The transistors are germanium...
This small AM transmitter was found in American documentation from the 1980s. Transistor support...