This circuit is from a 1980s Motorola documentation. The circuit can be made with modern equivalent components. The original circuit is for the 115 Vac (110 V) grid and has two settings.
The figure below shows an AC transconductance amplifier with the National Semiconductor LM3900. The...
This common circuit using operational amplifiers was found in the 1993 issue of Radio Electronics Special...
This circuit provides a voltage at the output only when the input voltage exceeds a value that...