Found on 80's Popular Electronics this circuit operates at 455 kHz. The explorer coil is formed by 10 turns of yarn 26 in a 4 inch shape. The indicator is a microammeter.
Found in documentation from the 1970s, this circuit uses an oscillator and a display to warn of...
This circuit indicates whether a cable or wire is energized by simply approaching its antenna. The...
Using bipolar, FETs and unijunction this long-lasting timer can reach 10 hours with good quality...