This circuit was found in a 1967 US documentation. The FET is general purpose and the 6V zener. The circuit has a very fast switching action.
Originally, this circuit is from an English magazine, but I found it in Argentina's Radio Chassis...
This electronic level or plumb indicator has two mercury switches as sensors. The indication is...
This circuit is from the 70's documentation. We kept the original text of the time. The so-called...