This circuit shows how to use an ordinary LED as a light sensor. It makes use of the photovoltaic voltage developed across the LED when it is exposed to light. LEDs are cheaper than photodiodes and ...

We know that LED is a two terminal semiconductor device. It is used in most of the electronic circuits as a sign or visual representation to the normal human to know that circuit is working properly.

High-brightness LEDs, with independent delay and duration, find use in a visual-inspection application. This circuit is not complex, but it saved the day in an application involving visual inspection ...