Created by takide
Status: Active

Joule Thief Flashlight Step 1 of 6


A Joule Thief is a special type of circuit that can squeeze every last bit of electricity out of your batteries. It works by storing energy inside a magnetic field, and then using the stored energy to "boost" the voltage up for a short amount time. This creates a short pulse of electricity with a voltage that is actually higher than the battery! The LED flickers on and off, thousands of times per second, which is too fast for our eyes to notice. This makes the LED appear that it is always shining!

Using the joule theif, you can make a 1.5v AA battery power a 3.2v, 10mm Ultrabright LED! The battery life is around 20-30 days of non-stop light using a AA battery.

In this kit, we will make an ultra long lasting LED flashlight, that is powered from a single AA or AAA battery. 

Parts List:

  • (1) 2N3904 NPN Transistor (A-111)
  • (1) 10mm Led (Any color)
  • (1) 8.2Ω Resistor (A-2640)
  • (1) Tact Switch (A-5144)
  • (1) AA or AAA Battery
  • (1) Nail (or Nut & Bolt) Must be magnetic!
  • 25ft of Enameled Magnet Wire