Originally suitable for photography applications, this circuit from a Popular Electronics from the 90s can also be used to time plate baths. The components are common, and the sensor is remote.
We found this circuit in an article in Electronics Now magazine from November 1997. The circuit uses...
This circuit provides just over ½ W to a small speaker. We found this configuration in an old...
In the figure we have a typical relaxation oscillator with a SIDAC as well as waveforms and...