This circuit that can be activated by light or heat was found in an old American documentation, but the components it uses are perfectly current. The power transistor shall be fitted with a heat sink.
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...