This circuit was found in the 1992 Radio Electronics Handbook. It is used to test VCR recording heads. It can also be used for other purposes.
This timer, from an old American publication, uses indicator lamps, but can be modified to use...
This didactic circuit from a 1977 Radio Shack documentation shows how to use the 741 as a...
Found in an 80's Hands On Electronics, this circuit turns on a light when it gets dark and goes...