Did you have problems winding the toroidal transformer of a regular joule thief? If so then this instructable is for you! And if not it is also an interesting circuit to see.
In this instructable I will show you how I made the simplest joule thief I know of with only an inductor!
Step 1: Demonstration
A joule thief is a circuit which boosts up voltage usually from a single AA cell to a higher voltage. It is most often used to drive LEDs with single "dead" battery.
Although the regulation is not as visible as it should. It's because I used a new battery. If you want to dim the light completely, use a 10kΩ potentiometer.
Step 2: Parts List
For this instructable you will need:
male headers (or you can just solder wires)
1x - BC327 small signal PNP transistor (others might work also but not as good)
1x - BC337 small signal NPN transistor (others might work also but not as good)
1x - 33µH inductor
1x - 470pF ceramic capacitor
1x - 47kΩ resistor
1x - 5kΩ or 10kΩ potentiometer or 2.2kΩ resistor(if brightness adjustment is not necessary)
Step 3: Schematic and Component Layout
The schematic is very plain and so is the component layout. I used the PCB layout as a guide for perfboard. I don't think making a custom PCB is worth it this time.
The original schematic can be found here: talking electronics
To make the schematic and component layout I used a free program CadSoft Eagle which I would recommend to anyone making schematics or PCBs.
Step 4: Conclusion
Although this may not be the most efficient joule thief ever, it gets the job done without the need of a toroid. The already small PCB could be made even smaller if SMD parts were used(but in reallity not by much).
Don't forget to post your results into the comments.
Luccaa made it!