Found in the March 1989 issue of Radio Electronics magazine, this circuit is used to test printer and other cables. The indication is made by LEDs.
In the circuit shown in the figure, we add a capacitor (C2) and a resistor (R4) at the base of the...
Indicated for calibrating digital instruments and circuits, this circuit was found in the June...
Found in an old English publication this circuit uses a dual gate MOSFET. Coils not specified....