This circuit decodes a 1800 Hz tone used in communications. The circuit is from an American documentation for radio amateurs of the 80's. Equivalent component can be used.
When the sensor X1 is opened, the relay is energized. When waiting, the current drained is very...
Based on the LF256 operational amplifier, this circuit was found in the September 1989 issue of...
This circuit was found in a 1968’s Motorola documentation. The transistor is from that time. The...