We have many tube tester circuits in this section. This one came out on a Radio Electronics from 1949 and has a very elaborate configuration with toggle switches.
We found this circuit in the April 1975 Radio Electronics magazine. The circuit has a latch and...
We found this sophisticated home alarm in a 1994 documentation. The circuit supports sensors of...
This circuit was found in the 1991 Electronics Experimenter's Handbook. It activates a relay when...