This simple timer for incandescent lamps or other non-electronic charges uses a triac as a control element. The triac must be mounted on a heatsink and the time obtained depends on capacitor C2.
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...