Found in a 90s Popular Electronics, this circuit uses a 741 to generate frequencies from 0.1 to 30 Hz. Observe the phototransistor feedback.
The same basic audio oscillator as the CIR15855E can be modulated automatically by a relaxation...
This configuration was found in a 1988 documentation. It is a touch lift drive system. The circuit...
We found this simple timer in a Raytheon documentation from the 60s. The transistor is made of...