This circuit uses a wire potentiometer, but the current is much more intense in the control thanks to the 2N3055 which must be mounted on a heat sink.
June 2017 - New Honeywell MT MICROSWITCH Series can be ordered from Mouser Electronics for...
This circuit for the very low frequency range was found in the Radio Electronics magazine of...
This circuit is from a 1992 publication, but can be mounted very easily today. The circuit is...