Help with joule thief circuit.

Thread Starter


Joined Mar 17, 2018
Hi, all.

I'm trying to build a very simple joule thief circuit. I'm using this toroid from Amazon. The circuit doesn't work and I have checked every connection, every pin, everything, and I can't figure it out. I'm attaching a picture of the schematic I'm following, and a picture of the circuit itself, since it's so simple that perhaps someone can spot a mistake. I can't.

I'm using a 1.5V battery, which is at more than 90%, a 1K resistor, and a 2N2222, in addition to the toroid mentioned before.


The red cable is positive and the white cable is negative. The transistor is upside down, so from this perspective and from left to right, it's CEB. The LED negative is facing right. Each pin of the toroid on the upper side of the board is connected to (ie. is the same wire as) the corresponding pin right underneath in the lower side of the board. There's a little piece of wire connecting the collector to the toroid. I don't know what else to check!

Please, help! Thanks!