When powering from a 1.5V AA battery, if you want to drive an LED that has a higher Forward Voltage (lets say 3.2V) and a forward current of 30mA, would you rather use a joule thief or a boost converter. From what I heard, a joule thief is terribly inefficient and seems to be some weird circuit where the voltage spike generated by the transformer is what drives the LED. Does that mean a boost converter will utilise energy more efficiently?

 

They both use the same basic principle. Connect a voltage across an inductor, allow the current to build, then switch off the current and feed the resulting back emf to the load. Good design of both would likely yield similar efficiences.

 

They both use the same basic principle. Connect a voltage across an inductor, allow the current to build, then switch off the current and feed the resulting back emf to the load. Good design of both would likely yield similar efficiences.

So it would be superfluous to bother buying a boost convert IC (i.e. from MAXIM) to step up the voltage where I could just have a simple joule thief.

Well now I just need to know how to determine the resistor, hFE gain value of transistor and transformer windings of the joule thief. Any tips and tricks to having a perfect result?

 

So it would be superfluous to bother buying a boost convert IC (i.e. from MAXIM) to step up the voltage where I could just have a simple joule thief.

Well now I just need to know how to determine the resistor, hFE gain value of transistor and transformer windings of the joule thief. Any tips and tricks to having a perfect result?

And that is the tricky bit - good design. With a maxim IC (other suppliers are available) they will provide the method to establish good values for the discrete parts. With a joule thief you're on your own.

 

And that is the tricky bit - good design. With a maxim IC (other suppliers are available) they will provide the method to establish good values for the discrete parts. With a joule thief you're on your own.

That's now my problem here. I guess i need to go to university and study electronical engineering. Unless i have some sort of lead. I got a very mediocre oscilloscope.