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.
We found this circuit at Modern Electronics in January 1991. The magazine no longer exists, but...
In this circuit, a jack with a diode activates a relay in a security system. The circuit is from a...
September 2016 - Supercapacitors of 10F to 100F in 3 V from Eaton can now be purchased from Mouser...