Fun with Joule Thief Powering a Compact Fluorescent Light

Demonstrations and testing of a joule thief circuit powering a compact fluorescent light (CFL) as requested by many who watched my "How to Make Joule Thief Light a CFL - Jeanna's Light" video. I show:
- how the light brightens using more batteries, including a 9 volt battery
- what effect the potentiometer/variable resistor has
- voltage and frequency measurements made using an oscilloscope at various points in the circuit
- using a solar cell to observe the light from the CFL, along with any flicker
- how to use a PNP transistor in the joule thief circuit instead of the NPN transistor
- testing how long the batteries last i.e. testing battery life, including mounting the transistor on a heatsink to solve a heating problem
- measuring current
- testing for interference with AM, shortwave and FM radio, analog TV signals and an LCD screen

More of my Joule Thief videos:

How to Make Joule Thief Light a CFL - Jeanna's Light

How a Joule Thief Works

Make a Joule Thief for Zombie Batteries to light an LED

To watch the "How to mount/attach transistor to heatsink (2N3055)" video:

To watch the "How to take Piezoelectric Igniter from Lighter for Spud Gun":

And for my webpage about joule thiefs, go to:

For Todd Harrison's fun electronics, DIY and more channel, go to:

To follow me on Twitter:

[ronaldgerth]

RimStar, to a Hobbyist such as me, you are a RockStar! Your videos are packed with fast paced information and lots of it. I am shocked that your channel does not have a million followers! 

[RimstarOrg]

Thanks and you're welcome. I taught for a software company for 15 years as well as various other smaller teaching jobs over the years. It's an addiction. :)

[RimstarOrg]

You're welcome! It's my pleasure making the videos. Thanks for watching and welcome to my channel!

[RimstarOrg]

Glad you like it. Thanks for watching.

[RimstarOrg]

Thanks Todd! It was definitely better thanks to your input. That whole analysis bit added to the solar cell part was your suggestion, and that's one of the best bits! The clickable annotations at the end aren't working at the moment, but hopefully when they do you'll get more visitors for your great videos. There's a link in the description too. Thanks again, my friend.

[RimstarOrg]

Thanks, and thanks for watching. Thinking back, I don't think I've ever seen them in things I've scavenged. I do see those flat, square, black types attached to heatsinks a lot, but I don't know their specs having never worked with them. Being attached to heatsinks, I imagine they have to handle power too. May be worth looking into.

[RimstarOrg]

Glad you liked it! Thanks for watching.

[RimstarOrg]

Thanks! I do take suggestions. e.g. This video wasn't even in the plans until I had so many questions and suggestions from my previous video. But unless there's a very large temperature difference and many thermocouples I suspect, there won't be enough power to run this circuit, even with the low power transistor version. Maybe a themocouple powered by concentrated solar sunlight would work though. The Voyage RTG used a hot-cold temperature difference of 700C or 1260F.

[RimstarOrg]

I don't know if silicon solar cells make use of infrared though I suspect not, or not much since that's one of the advantages of multijunction gallium arsenide solar cells.
And thanks man! Glad you like the video.

[RimstarOrg]

Thanks! If I recall it can handle up to 1000 volts. It also helps that they're spaced out spikes.

[RimstarOrg]

Thanks! I'll take awesome any day. Glad you liked it.

[RimstarOrg]

It's the same as for an NPN transistor, the only thing that changes in the circuit is to reverse the battery. I'm also guessing you mean an LED, but I've included enough info in case you mean a regular diode. The short leg of the LED/the negative/the cathode/the end with the stripe goes to the transistor's emitter. The other end goes to the transistor's collector.

[ryanjhi]

igreat video! incredible that the scope wasn't damaged by the 700 volt input

[RimstarOrg]

Thanks. Glad to hear is was worth the wait.

[RimstarOrg]

Thanks. And I looked for the Ah but they never seem to include them, not even on the packaging. As for the turns, I wrapped them myself so sure. It's the same coil from last week's video. 256 turns of 30 AWG, then 10 turns of 24 on top of that, followed by 5 turns of 24 on top of that (I mistakenly said 18 AWG for the two 24 AWGs in the video.)

[RimstarOrg]

Thanks. And I'll take your word for it. I'm no tesla coil expert, though I'd like to make one at some point.

[RimstarOrg]

I don't know any temperature ranges. I just felt and if it was too hot to touch after a second or so I figured it was getting hot and I probably didn't want it getting hotter.

[RimstarOrg]

Thanks. Since you replied to me, simontay1984 may not get notified so I replied to him to see your comment.

[Slider]

Good set of tests, very thorough. A 1W LED mains bulb would seem ideal for this circuit...and rechargeables.

[FungSit]

I was thinking of using little power such as a few batteries to drive high voltage AC appliance (I actually want to make a fume extractor) now you point me to a shortcut. Thanks. It's really surprising to me though, that the "spikey power" can drive CFL, I need to investigate why this will work for CFL, but not some other devices.