Found in a Popular Elecronics from the 90s, this circuit appears in other versions in this section and on the website. The circuit draws one of 10 LEDs and has a sound effect produced during the draw.
This circuit can source up to 1,000 V from a 9 V battery. Output current is very low, some...
This circuit detects the presence of strong signals from spy transmitters, enabling their...
This circuit of a publication from the 70's uses a different type of power that we had already...