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.
Found in a Popular Electronics from the 90s, this circuit uses a double 555 to emit beeps when the...
This circuit was obtained from National Semiconductor documentation from the 1990s. The circuit has a...
This RF monitor or field strength meter can use instruments from 100 uA to 1 mA full scale. The...