This is one of the many modulated siren versions that can be found on our website. We found it in a Hands On Electronics from the 90s.
This interesting circuit measures the distortion of the sinusoidal voltage of the power grid. We...
The operational amplifier used in this old application is not common today, but more modern...
Used in 1950s CW receivers, this type of circuit used germanium transistors. The circuit has...