This circuit is from a Mallory 1968’s documentation. The integrated circuit is of the time and the transistor admits equivalents.
This circuit was found in the May 1989 issue of Radio Electronics magazine. The circuit requires a...
We find this microphone voice effect in 1992 documentation. The vibration of the relay contacts...
This circuit to increase the sensitivity of instruments to 100 uA (or close to it) was found in...