This medium power circuit is from an English publication from 1989. The integrated circuits are of types that are still obtainable. The power supply must source at least 2A.
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The LEDs, in addition to flashing if the transistor is good, also indicate the polarity of the...
This circuit was found in a 1980 documentation. It is an interesting 3-track radio circuit whose...
This alarm circuit was found in the July 1992 Radio Electronics magazine. The circuit uses a small...