This circuit was found in a Popular Electronics from the 90s. The circuit has 4 frequency ranges selected according to the capacitors. Signal is rectangular.
This 3-and-a-half-digit voltmeter was obtained in a 1991 documentation. Actuating integrated...
Currents of a few milliamps are enough to drive loads up to 500 mA with this circuit. The...
This circuit was found in Mullard's transistor application manual from 1960. More modern...