This simple continuity tester consists of an oscillator found in the 1983 Electronics Experimenter Special projects magazine. The circuit is powered by a single battery.
When the light falling on the sensor is cut off, the SCR fires, powering the lamp. Remember that...
We found this circuit in Radio Electronics from October 1968. The circuit drives headlight bulbs...
This 8.2 V voltage reference was found in a 1968 Electronic Design. The op amp is from the time,...