Using a capacitor as a sensor, this circuit was found in the 1989 Radio Electronics Experimenter magazine. The circuit must be assembled in a shielded box.
We find this circuit in American documentation from the 1980s. The accuracy of the circuit depends on the...
The presented circuit uses a symmetrical power source to supply an amplifier with the LM139 or...
High quality sound can be obtained from this transistor amplifier. The output transistors must be...