Joule Thief LED Flashlight (Free Light)

This is a Joule Thief Flashlight. I simply modified a cheap 5 super bright LED flashlight that ran on 3 AA batteries by gutting it and using a simple Joule thief circuit which now runs on 1 AA battery. This circuit uses a 2N3904 transistor, a 1K resistor, 1″ ferrite toroid, and 22 gauge bifilar wire windings. The components cost less than $3.00. This is easy to do and it is a fun project for everyone. This light will run on “dead” batteries. Most devices will stop operating when the 1.5 volt battery gets down to about 1.2 volts or so. This JT circuit will take that dead battery down to about .3 volts. This video was filmed using a “dead” battery. I get them for free from my friends and this way, I get to use all of the energy in the battery before we toss it out. The light will work for many, many hours on a dead battery. Way longer than using the 3 AA batteries (new) that came with this cheap light. For more information, go to in the Joule Thief topic. Free light from “dead” batteries. Thanks for watching.

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