This TTL counter was found in the April 1979 issue of Radio Electronics magazine. The circuit is powered by 5 V and has a pulse generator for educational or experimental purposes.
This circuit, found in a 1988 documentation consisting of an audio switch that turns off the load...
This stabilized source can supply currents up to 200 mA with the indicated transistor or 500 mA...
With the shadow over the sensor, it is possible to interrupt the sound of your amplifier using this...