Metal detector receiver (CB22457E)

Found at Popular Electronics this receiver is used with a transmitter for quadrature-coil signals.

733 or 592 Video Amplifier (CB25469E)
This circuit is from a June 1992 Radio Electronics. The circuit is for 4.5 MHz signals from old...
Centigrade Thermocouple Thermometer (CB6023E)
This circuit, calibrated to the degree Celsius scale, was found in a National Semiconductor...
Photo Control (CB16342E)
The photocontrol that we give in this project of a 1982 documentation allows to activate a circuit...