My joule thief in cfl.

[Pirate88179]

I still seem to have trouble reproducing this image!! as I did in 2009.
If anybody can rescue this again this was the posting containing the image cheers:  Re: Jule Thief  « Reply #11001 on: December 22, 2009, 10:06:28 PM »

I will give it a try to see if it works here:

Bill

[ACG]

Is it as simple as an 1800mah battery would run a circuit at 1800millamps for 1 hour.

That calculation is good for a quick approximation.  The capacity ratings are actually computed from drawing a smaller current over many hours.  The greater to current draw the greater the power lost inside the battery.  You would need to see what the C rating for discharge is for your battery such as 1/2C, 1/5C, 1/10C.  1/10C discharge would mean you can draw 180milliamps for 10 hours.  But if you were to draw 1C it would not last 1 hour.

But this being a joule thief you get more out of it by design.  The discharge C rating is the standard for a technically dead battery, there is still LOTS of energy inside it when technically dead.


Is the 220ma measure from the bulb or from the 2 AAA batteries?
Ebay 'brand' of batteries are notorious for over stating the capacity.

[MarkE]

That's all true.  Both Duracell and Energizer offer helpful engineering information on their batteries.  Lots of applications consider an alkaline cell dead at 1.2V.  Better products run them down to 0.8V - 0.9V.  If you extrapolate the curve on page 2 of the attached Energizer AA data sheet, a fairly light load like a radio ~17mA @ 0.8V still has about 510mA hours capacity down to 0.5V, or another 1200J to give.  That's about 10% of the battery's capacity between fresh and 0.8V. 

[crowclaw]

@ Pirate

Many thanks Bill... Not the best pic as the lens shuts down with the light intensity of course.

Kind regards Merv

[Pirate88179]

@ Pirate

Many thanks Bill... Not the best pic as the lens shuts down with the light intensity of course.

Kind regards Merv

No problem Merv.

Bill