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.

Light change detector (CB22058E)
This circuit only detects variations in light falling on the sensor. The circuit uses an LM380 as a...
Operational Pulse Generator 2 (CB14831E)
We found this circuit in a French technical documentation from 1982. The circuit can be...
Instrumentation Amplifier (CB14090E)
This amplifier with differential input uses two old op amps but can be implemented with modern op amps....