This circuit is from a 1968 publication. Here we have several types of resistive sensors with individual adjustments triggering a single SCR. Power depends on the type of sound device to be triggered.
This circuit can be used as a lockable shield. A pulse activates the relay that remains on even...
Found in a 90s documentation, this circuit makes use of D1, a switching diode that is uncommon today....
June 2017 - New Honeywell MT MICROSWITCH Series can be ordered from Mouser Electronics for...