This simple bridge circuit can be used for impedance or resistance measurement using a high impedance earphone as an indicator. The circuit is from an American 80's documentation.
An excellent signal generator for the audio track was found in a 1983 documentation. Its complete...
CMOS inverters can be used as amplifiers, obtaining a flat response up to approximately 20 kHz....
This circuit uses BCD switches to program the frequency to be divided. The circuit is from a Radio...