Joule Thief

Hi there today I would like to show you an exciting thing, it’s called Joule Thief. What’s Joule Thief? It’s a simple circuit which consists from single transistor and bifilar coil. It’s circuit that will allow you to turn on LED on 1,5V.

Well Joule Thief it’s a great thing, you can use your old almost dead batteries to light up LED at full brightness. So I’ve decided to create it at first I’ve tried to use industrially created coil’s, but they weren’t good, so I’ve bought ferrite toroid and I’ve wounded coil. I’ve tried few transistors and few versions of coils and I’ve ended with BC549C and with something like 40 turns on coil. I was able to create 36 volts from almost dead 1,5 v battery. So build yourself one and try what you can do with it. Down there you can see circuit and videos of mine Joule Thief.

Later I've tried to hook up Joule Thief to a kitchen batteries, which are ones that uses electrolytes from stuff you can find in kitchen just like vinegar, baking soda and lemon drain.