Found in the May 1971 Radio Electronics magazine, this is the circuit for a commercial high-impedance instrument. The circuit uses 4 transistors and is powered by 2 9 V batteries.
Using transistorized regulators with NPN and PNP transistors we can create a symmetrical source of...
This circuit was found in a 1997 documentation. The signals are adjusted in a double 555 (556) and the...
We find this circuit in a 1980s documentation for amateur radio. The circuit shows how to switch...