This circuit triggers a buzzer or other warning device when the light falling on the sensor is cut off. We found it in the Encyclopedia of Electronic Circuits Volume 5 of 1995.
Originally intended to detect EMPs produced by tests or atomic blasts, this interesting circuit...
This circuit triggers a small water pump when the humidity detected by the sensor is reduced in a...
This circuit was found in Maxim's documentation from the 90's. The configuration uses components...