This 90s Motorola circuit from, has current limiting foldback. The power transistor is from the era, and equivalents can be used. The output is 250 V.
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...