This medium wave radio works with any general purpose NPN transistor. The diode must be made of germanium and a coil formed by 50 + 50 turns of wire 26 to 30 on a ferrite rod.
The 78XX series voltage regulator integrated circuits do not support an input voltage greater than...
This is the complete circuit of a multimeter using a 50 uA instrument with a 2k coil. The circuit...
This circuit came out in a Popular Electronics from December 1995. It is a double T configuration that...