Found in an 1868 Mullard documentation this circuit has a dynamic range of 10 Hz to 25,000 Hz. Modern equivalent transistors can be used.
This circuit is from a 1968 Electronic Design. The components are from the era and the operating...
ON Semiconductor CMOS Operational Amplifiers Mouser Electronics announces the availability of ON...
We find this circuit in an American 1980s documentation. It triggers an alarm in the event of a...