This circuit is from a March 1978 Radio Electronics magazine article that showed how to build it. The circuit is TTL based and is powered. The components used can still be found.
We found this circuit in Harris' 90s documentation. The circuit applies to modern operational...
This circuit makes it possible to use a low impedance headset as a microphone. The circuit, on a...
This Baqxandall tone control can be used with any low Power audio stage as the input of a audio...