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.
Measuring capacitances and resistance this simple instrument was found in Radio Electronics...
The LM143 integrated circuit is a high voltage operational amplifier from National Semiconductor that is...
We found this circuit in the November 1985 issue of Radio Electronics magazine. It uses TTL...