On the basis that it's me who actually named the Joule Thief, it's about time I actually put up a video showing how to make one.
This video shows a version that is true to the original design sent in by the mysterious Z Kaparnik to the Ingenuity Unlimited section of an electronics magazine called EPE. I just loved the simplicity of the circuit and built many of them. Latterly when the Internet "happened" I added it to my website as a project and gave it the snappy name Joule Thief on the basis that it steals all the last energy from a battery. The combination of the circuit's amazing simplicity, functionality and the fun name just developed a life of its own on the 'net.
There are a few variants on the design which add extra components to improve efficiency, but a true Joule Thief uses a single transistor, 1K resistor, hand wound ferrite bead transformer and the LED you want to light.
The circuit is just incredibly rugged. It can be used with just about any small ferrite toroid or core you can find. It's great for use with the little ferrite rings found in the circuitry of dead compact fluorescent lamps.
The wire you wind it with can be new or salvaged lacquered wire (used in transformers and relays), and the gauge of the wire isn't too critical. The transistor is a general purpose small NPN transistor. You can either use the suggested one or just whatever you can find in your electronic hoard.
This video shows a version that is true to the original design sent in by the mysterious Z Kaparnik to the Ingenuity Unlimited section of an electronics magazine called EPE. I just loved the simplicity of the circuit and built many of them. Latterly when the Internet "happened" I added it to my website as a project and gave it the snappy name Joule Thief on the basis that it steals all the last energy from a battery. The combination of the circuit's amazing simplicity, functionality and the fun name just developed a life of its own on the 'net.
There are a few variants on the design which add extra components to improve efficiency, but a true Joule Thief uses a single transistor, 1K resistor, hand wound ferrite bead transformer and the LED you want to light.
The circuit is just incredibly rugged. It can be used with just about any small ferrite toroid or core you can find. It's great for use with the little ferrite rings found in the circuitry of dead compact fluorescent lamps.
The wire you wind it with can be new or salvaged lacquered wire (used in transformers and relays), and the gauge of the wire isn't too critical. The transistor is a general purpose small NPN transistor. You can either use the suggested one or just whatever you can find in your electronic hoard.
there's no circuit board needed for this… nor clamp or any other soldering assist tools
What's amazing to me is your "third hand" you have on your left hand to hold the solder 🤣🤣🤣
You need to take up smoking gars rather than drinking buddy lol.
can I put fresh cells in there ?
Ah … my daily dose of BCDC sorted!
Dippy Hippy (as was until YT stuck its oar in)
This thingy makes me scratch my head
Clive, in the nicest way possible, your videos are ALMOST as good as listening to rainfall sounds to fall to sleep to 🥰👌
I wonder if this circuit could be used to build a oneshot triggerable LED strobe light… I have just started fiddling with electronics, because I want to have an LED strobe light I can control from a Raspberry Pi and sync it to music.
I've seen there's some really neat white LEDs that can eat up quite a lot of watts. I am wondering if I could somehow step up a 5V 300 mA input voltage (so it can be powered from a USB power bank), charge a capacitor and then use a GPIO pin from the Pi to control a transistor to discharge the capacitor into the diode, creating a short, bright flash on demand…
I have some idesd, but too many unknowns still. Maybe someone had done something like this and shared how and why?
Thank you for your videos!
Question: My Mom has a string of LED's, and I've been saving up dead AA, AAA and C batteries — Can I scale up the, "joule thief," circuit to service her purple little lights?
Love your website, and thanks for the videos!
Would it drive a little UV fluorescent bulb for a pocket money detector?
I did some experimenting
Yes, just like Clive said, you need a ferrite core, but ferrite cores have many shape and sizes
So i went ahead and test a ferrite core from an SMD inductor (remove the old windings and rewound it just like clive) and….it worked, beautifully too.
Same with through hole inductors (the black one with the heat shrink tubing)
You can really compact these down to a finger
I've just bought one of those multimeters from our local cheap goods emporium. Kind of makes me feel good that you have one too. Hope it's still working 🙂
"Parma Violents"
i've avoided this video because i thought it's something you plug intot a wall socket and at the end of the month owe the power company 7 million.
Could you replace the led with a spark gap, and adjust some values to generate sparks?
Now why do certain electronics only use a small bit of the capacity of a battery? Is it to buy more batteries? Seems like a waste.
i feel like a few more fingers would make the job a little easier