Ultrasonic Proximity Sensor (CB21312E)

This circuit was found in a Popular Electronics from the 90s. The circuit uses a ceramic capsule as an emitter and detector.

Gain control with 741 and JFET (CB25572E)
This circuit was found in the April 1993 Electronics Now magazine. With it, it is possible to...
4-Digit Digital Multimeter (CB24735E)
We found this circuit in the February 1983 issue of Radio Electronics magazine. The 4-digit...
Selectable staircase generator (CB9341E)
This circuit was found in Philips documentation from 1967. The circuit uses components of the...