This extremely slow circuit produces one pulse per month and can be used in a timer. We found it in the November 1998 Electronics Now magazine.
An old analog TV that is not in use can be turned into an oscilloscope for low frequencies...
This circuit can be used as a base for a UHF transmitter or even a test equipment. The circuit is...
Virtually any FET can be used on this voltmeter found in old documentation. The indicator is a...