High impedance differential amplifier (CB9838E)

Based on operational amplifiers of the time, this circuit from the 1980s has high input impedance. The power supply must be symmetrical.

Self-powered monitor (CB8983E)
Placed in the vicinity of a telegraphic transmitter (CW), this circuit produces an audible signal on...
Optical Transmitter (CB4953E)
This circuit for light data transmission (visible or IR) has a maximum speed of 1 Mbps and can be...
Electrolytic recoverer (CB7074E)
This circuit aims to recover electrolytic capacitors by applying currents higher than normal for a...