Joule Thief

[Pirate88179]

RE: Little Miss Mosfet

I think I still have beer somewhere down inside my keyboard from when I spit it out laughing while reading TK's above nick name for Rose.

That one will always remain a classic.

Bill

[MarkE]

Piratebill, my Mouser order came in.  I hooked up a PAM2803 to one of those Harbor Freight lights after taking out the current limit resistor that was in series with the 24 LED array and driving the LEDs at 200mA.  At 2.4V for the batteries the current draw is about 360mA.  That means that with a pair of AA alkaline cells in series you should get 6-7 hours.

[Pirate88179]

Piratebill, my Mouser order came in.  I hooked up a PAM2803 to one of those Harbor Freight lights after taking out the current limit resistor that was in series with the 24 LED array and driving the LEDs at 200mA.  At 2.4V for the batteries the current draw is about 360mA.  That means that with a pair of AA alkaline cells in series you should get 6-7 hours.

Mark:

That sounds pretty good to me.  So, the PAM2803 can run on 2 cells in series?  In other words, I could modify the HF light to have 1 AAA in parallel and leave the other 2 in series and get an even longer run time...right?

I will have to order some of those chips.  Thank you for testing this and telling me.

Bill

[MarkE]

Mark:

That sounds pretty good to me.  So, the PAM2803 can run on 2 cells in series?  In other words, I could modify the HF light to have 1 AAA in parallel and leave the other 2 in series and get an even longer run time...right?

I will have to order some of those chips.  Thank you for testing this and telling me.

Bill

You would use two AA's in series period.  The PAM2803 is designed to operate from a pair of AA alkaline or NiMH cells in series.

[tgraca]

I have been playing with this on and off for over a week now.
Here's a summary of my final 6 tests with the 2N2222A transistor, which in previous tests performed better than the 3904.