Joule Thief, very funny name. As it is showing its name that it is a Thief that theft Joule means power.
This Jewel Thief circuit is a special type of circuit that can boost your ampere power in such a way that you can easily run a 12 volt led by just simply use in a 1.5-volt cell.
What is a Joule Thief?
A joule thief is a minimalist self-oscillating voltage booster that is small, and easy to build, typically used for driving small loads.
You can drive small loads through the circuit such as you can easily drive a 12 volt LED using a 1.5-volt cell or 3.7-volt battery.
This is a special circuit that you can use to make a 1.5-volt battery torch and in many projects.
1) 20T-20T Toroid
2) 2n2222a Transistor
3) 1K Resistance