This circuit uses a contactor having been found in a 1987 publication. More modern equivalent devices may be used. The circuit has neon indicator lamps.
This capacitive switch or approximation relay was found in a 1980s US publication. Power should...
Based on the LF256 operational amplifier, this circuit was found in the September 1989 issue of...
This circuit is a kind of Hertz Loop that can be used to check the operation of transmitters and...