148Views3Replies

Author Options:

Joule thief? Answered

http://joulethief.com/kit.php : It was from here that I built my first working joule thief. (I've found better ones now.) Anyways, last week, I got bored and tried to destroy an LED by feeding the circuit more and more power...I got to 18V (laptop charger adapter) and it still didn't bust. Why?

Comments

The forums are retiring in 2021 and are now closed for new topics and comments.
0
frimm
frimm

Best Answer 10 years ago

 The joule thief does its work when the transistor turns off. With a higher than normal voltage, all you're doing is keep the transistor on much longer, which will do nothing but burn up power.

I suspect all you get is an uncomfortably warm coil.

0
coolpizzadude
coolpizzadude

10 years ago

For some reason the input voltage dose not greatly affect the output voltage but I have know idea why.

0
Re-design
Re-design

10 years ago

The coil must be limiting the current thru the led.  The transistors are also taking up some of the load.

Or maybe it's just a super-led!