Crystal oscillator (CB9504E)

This circuit was found in a 90s Popular Electronics. It can generate signals from 3 to 10 MHz.

Proportional temperature controller (CB21277E)
This circuit is from an Electronic Design from the 90's. The main integrated circuit is uncommon...
Basic dimmer with triac (CB25882E)
This circuit is from an Electronics Now from August 1995. The triac is according to the load that...
Timer (CB12979E)
This timer activates a relay after a time interval of up to 15 minutes has elapsed, starting from...