Found in General Electric's documentation from 1970, this circuit is indicated for the so-called “Solid State Lamp” (SSL). The LED symbol in the original diagram is inverted.
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...