This circuit can be used to test up to three LEDs at once, connected in series. You can easily increase that number by using a higher supply voltage. If you do so, you should allow 2.7 V for each ...

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 ...