This circuit was found in the July 1995 issue of Electronics Now magazine. The integrated circuit is an RCA-era type. The triac must be equipped with a heat sink.
Carbon microphones are no longer used in most projects. However, finding one in the scrap metal, it...
This circuit produces a strong tone of audio or ultrasound, depending on the values of components C1 and...
This alarm from an old 1978 publication uses PNP transistors and driver and output transformers that are...