Joule Thief

About: Crafter, Builder, tinker, potter tailor .... Na just a guy that loves to make things especially if it means making a difference to the world and my impact on it

Well i have been exceptionally silent but not lazy... Been working full time and have a new awesome projects i am going to share. This one is a teaser still not a full step by step as i will edit this in the next few days to add detail but for now here is the teaser. Making a Joule thief lamp to run a high powered 3.3v super white LED from a 1.1v (used 1.5v) battery. This was the start but if you know our site you will know we all about green, read on for the twist.. So step one .....

Step 1: Build a Joule Thief

I followed this diagram to build my first one. This is so simple you almost cannot go wrong. Except to forget to wire the coil so the windings run in opposite directions. The best way i find to wrapp tje toroid is to strip about a meter of network solid core cable. Then make 20 windings. In the end you will have 4 ends join 2 ends each different colour, but here is the trick.... Take the start of the one colour and the end of the other colour and join them. I find it easier to put the resistor on the base of the tranistor for ease of construction.

Step 2: Working Lamp

Now once you have a working thief you can build it into a lamp of any description..... As per my original pic. This step shows my lamp working on a partially deplkeated aaa battery. At the time it was sitting at 1.3 volts...... Now for the twist.

Step 3: The Twist

I hate the fact that i must rely on a battery.... So i made my own. This is a glass coffee bottle, i enjoyed every cup i made from the coffe it once contained. I installed a joule thief in the lid with 2 ultra bright LED in lid shining into bottle in parallel. I then turned the bottle into a battery with bleach. The voltage when off is 1.4, running it is 0.7 so far it has been running for 72h no stop and still good as a night light. After 72 hours voltage at 5.8v..... The best part is total cost is less than R5.00 or about 50 usd cents....... watch this space for details and do not forget to visit us at for more ideas and projects

Step 4: Running

This is my bleach driven joule thief night light in action. So remember this is a short version as was to exited to share and did not want to add the detail tonught.



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    3 Discussions


    Reply 4 years ago on Introduction

    So far the best result i have had with this is using a coil of copper wire from a 15amp ground cable, about 30cm that i coiled round a pen. I then took a aluminum can (red bull) sanded it on both sides to get rid of plastic .... using a wet wipe as a insulator wrapped one the can round the wire. filled it with a bleach solution of 15ml to 500ml water ... this gave me a 1.2v (my amp meter down so can not read that part) ... has kept the joule thief going for 2 weeks which is pretty good so far i think. in progress of making version 2 ...without the tissue to improve electron circulation....