This circuit was found in the April 1971 Radio Electronics magazine. It uses common transistors and can be adapted to use an LED or audible indicator instead of a light bulb.
This project is of great use as it serves both to feed test equipment as well as to the component...
This conventional slow-moving circuit uses incandescent light bulbs, but can be changed to use...
This circuit generates sawtooth signals whose frequencies depend on the values of the selected...