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 ...

Some 1.5 v LED flasher circuits are available on the internet and we like to present you four of them. The flasher circuits below operate on a single 1.5 volt battery. The circuit on the upper uses ...

What do you get for the geek who has everything and likes LEDs? A tricked-out LED tester, naturally. [Dave Cook]’s deluxe model sports an LCD screen and two adjustable values: desired current and ...