This circuit activates a horn from an audio signal. This can be used for remote control via audio signals. The circuit is from a Radio Electronics from October 1965.
We found this circuit in old American documentation. It can be implemented with more modern...
The purpose of this circuit is to control the high and low light of a car, detecting when a...
This powerful transmitter for the 27 MHz band was found in a Japanese publication from 1961. The...