We found this circuit in the August 1990 issue of Radio Electronics magazine. The two-digit circuit uses a pressure sensor and is powered by a 9V battery.
If you have a disused old computer, the type that still has a parallel port, you can use it in...
Using earphone for listening, this receiver has only one germanium transistor. The circuit is from...
This oscillator can generate signals up to a few megahertz depending on the crystal used. Actually...