Found on an 80's Elektor, this circuit uses common components, being the diode a general purpose germanium. The coils select the frequency range of the indicator that reaches 60 MHz.
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...