7-segment display driver (CB20551E)

We found this circuit in English documentation from 1996 for PCs. The circuit is for common cathode display.

Power Grid Distortion Meter (CB23629E)
This interesting circuit measures the distortion of the sinusoidal voltage of the power grid. We...
Voltmeter (CB19740E)
The operational amplifier used in this old application is not common today, but more modern...
50 KHz IF (CB22243E)
Used in 1950s CW receivers, this type of circuit used germanium transistors. The circuit has...