Found in a 1990s US publication, this alarm circuit detects when a light beam is interrupted. Optical resources may be used for the sensor and instead of the alarm a relay may be used.
This simple TTL circuit indicates which was the first to press one of the four pressure switches. The...
September 2017 - Panasonic Dy2L TVS diodes for network applications, security, medical equipment,...
This circuit was found in a 90s Popular Electronics. It is used for the acoustic transmitters of 40 kHz,...