This circuit was obtained from HAM Radio magazine in an 80's issue. The FETs are types of the time and the frequency is determined by the crystal. The circuit operates at voltages from 3 to 9 V.
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...