This circuit was found in a documentation of the 80s, having didactic purpose. For R1 values between 10k to 1M can be used. Transistors are general purpose types.
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...