This alarm goes off if someone leaves a door open. We found it in the Encyclopedia of Electronic Circuits Volume 5 from 1995. The circuit uses components that are still common today.
The components of this circuit are still common today. The circuit is from a 1967 publication by...
This analog TV circuit can be used on a small transmitter. The circuit is from an 80's American...
We found this circuit in a 1976 documentation. The FET can be BF245 or MPF102 and the power supply...