The idea of this circuit found in a Radio Electronics from January 1966. The idea of the circuit is to improve the reception of audio signals, mainly telegraphy, working as a filter.
The circuit shown in the figure activates a small indicator lamp that will start to flash when the...
The circuit shown is from National Semiconductor's Linear Applications Handbook. The LM3900 is a...
This circuit was found in a 1976 documentation. It can be used with old tape recording mechanisms for...