Found in an 80's Elektor, this circuit can use any equivalent optical coupler. The buzzer is of the Sonalert type with included oscillator.
This circuit is an excellent application for the PIC in audio, but the reader who intends to do...
To a 16-0hm load, this amplifier provides a power of 10 W. We found this circuit in a Motorola...
This reader with TTL logic compatible output uses an LM139 comparator. The circuit was found in...