This circuit is from a Radio Electronics from April 1964. The circuit uses power transistors of the time, which must be mounted on a good heat radiator. Modern equivalents can be used.
This circuit is originally recommended as hearing aid or stethoscope. The output transducer is a...
Originally suggested by Popular Electronics to control Christmas lights, this circuit can...
The purpose of this circuit is to detect output signals from a transmitter for the frequency range...