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.
We found this circuit in the 1994 Linear Applications Handbook from National Semiconductor. The...
This circuit is from an Electronics World of 1968. The transistors are of the time and the power...
This circuit checks the infrared emission of a common remote control. We found it in the March 1993...