Using an operational amplifier of the time, this circuit was obtained from a 90s Radio Electronics. The circuit covers the frequency range from 2 Hz to 20 kHz.
We found this circuit in the March 1992 issue of Radio Electronics magazine. The circuit has a...
The circuit presented may use any general purpose transistor. The indicator is an LED and...
This unusual audio amplifier configuration was obtained in a 1974 documentation. The PNP...