Linverter! Step-up circuit test with pics!

So, after bugging Doug Owen about a step up circuit he finally gave in and bought a few "linverter" circuits from www.linverter.com. I've been wanting to make something like this since seeing the first "joule thief" website.

I stopped by his mad scientist hang out and picked it up. Took me a bit of fumbling to put together (novice that I am) and I got it to work. Boy is this thing cool!

I found the most dead batteries in my box and decided to do a test. I grabbed two identical flashlights and put my two "dead" batteries in one and two fresh batteries in the other. Below is a comparison pic (notice how dim the light on the right is:



I then took the "dead" batteries out and put them in my linverter. Here is the flashlight with the good batteries along with my new circuit:



I think it's interesting that the flashlight now looks like the dead battery light when compared to the LEDs!

Keep in mind that this would have looked just as cool with one of the batteries, but I didn't have a single AA incandecent flashight to do a side by side test with /ubbthreads/images/graemlins/wink.gif

Here is the circuit:



For more pics, visit:
http://www.nifty-stuff.com/gallery/album01

Comparing an incandescent with a pair of LEDs? Tsk tsk shame on you! /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/wink.gif

Rob,

Wow, this is cool, didn't take you long to cobble it together. I'd be a bit careful of overdriving two LEDs with inputs over about two volts as I recall. The one I built (and put a one ohm in series with the output to measure current) was pushing 30 mA a diode with *four* with three volts in. FWIW, going much higher gets you in real trouble as Vin gets close to Vf.....

Kind of a fun circuit, easy enough to build (if somewhat homely when done), just the ticket for 'draining the weak ones' if that's where you're at. At $7 for the kit, it's for the few with the taste for such stuff, IMO. Then again, it was quick (prompt airmail from the UK) and the price includes delivery to a huge list of countries.

Anyway, glad you like it, not sure what I'll do with mine yet.

Linverter

Doug Owen

Doug,

I thought of that when designing. I considered the fact that I would only be using this with either one cell, or two reeeaaaly dead cells, so I'm hoping it won't be a problem... besides, I've got a bunch of these 5000 mcd 5mm LEDs from ebay I gotta get rid of (can you say overdrive?) so I can get the new 10,000 mcd ones!

I'm sorry, I didn't realize this was a serious experiment...

As a bit of advice, if you're thinking of running out the low output LEDs like the half dead cells you've got stashed away in various places, you're going to need some more circuits.......

In a (at least slightly) more serious vein, this does seem to be an answer to 'what do I use to drain all these half dead batteries?'. Even though they really mean 'cells', this seems to take care of 'em in singles or pairs. Down under a volt (total) in the (single) one I have.

Doug Owen

Hi,
I have just found the website. I am interested in building one of the linverter circuits or buying one complete to help me with a new torch development which I am working on. Is it possible to get a circuit diagram and/or parts list so that I can build one. I will need an idiots guide for this as I am not electronically minded.

Thanks

Hi Kevin - there is a link in post 3.

Welcome to CPF.

Harry

The site is sold out of the Linverter kits. Does anyone have a schematic for the circuit?

Thanks, I have already tried the link and they say that they have no stock and their e mail address will not accept any mail. I was hoping to find another supplier.

OK, I understand about not wanting to post the Linverter schematic.

This circuit works excellent with 1 LED, but I have misplaced my notes on adjusting the current to the LED. What value would R1 and C1 have to be changed to drive 3, or 4 LED's?

This is a really good question - but perhaps it would get more answers in the battery / electronics section ? Maybe a mod will move this thread over there for you ?