Found in a 1991 PE Hobbyst Handbook, this circuit activates an oscillator that deactivates at the end of the programmed time. Transistors are commonly used.
In the original 1992 application, this passive circuit was intended for use in the car. At that...
This 1995 circuit uses an audio amplifier that is no longer common today. However, other...
This circuit is from an 80's documentation. The integrated circuit is from the time and the...