Joule Thief

[xee2]

Pirate88179



The blinking Joule thief in my web page post at:


http://www.youtube.com/watch?v=-l7L_u45edE&feature=c4-overview-vl&list=PLNujarhoynFkpZZasJ6v9Yrva0-a9vDZZ


which uses 0.028 mA, will theoretically run for 9 days using a 10F capacitor that drops from 1.5 volts to 0.7 volts. Some of the other Joule thiefs I built would run for over 60 days. I have not run a test to verify this, but I will if I ever get a 10F capacitor.


The human body powered Joule thief circuit should also run for about 9 days using a 10F capacitor:


http://www.youtube.com/watch?v=gNbPpG0ezxM&feature=c4-overview-vl&list=PLNujarhoynFkpZZasJ6v9Yrva0-a9vDZZ

[Pirate88179]

Pirate88179



The blinking Joule thief in my web page post at:


http://www.youtube.com/watch?v=-l7L_u45edE&feature=c4-overview-vl&list=PLNujarhoynFkpZZasJ6v9Yrva0-a9vDZZ


which uses 0.028 mA, will theoretically run for 9 days using a 10F capacitor that drops from 1.5 volts to 0.7 volts. Some of the other Joule thiefs I built would run for over 60 days. I have not run a test to verify this, but I will if I ever get a 10F capacitor.


The human body powered Joule thief circuit should also run for about 9 days using a 10F capacitor:


http://www.youtube.com/watch?v=gNbPpG0ezxM&feature=c4-overview-vl&list=PLNujarhoynFkpZZasJ6v9Yrva0-a9vDZZ

Xee2:

Yes, nice work.  I remember seeing this a while back.  Instead of the MPSA06, which I think you said will go down to .7 volts, have you tried the new FJD5553 from Fairchild?  It should work to down below .2 volts.  Also, it can handle a lot of power as well.  (within reason)  Your circuit should then probably run for maybe 12 years or so?  I have been playing with them for the past month or so.

Very well done Sir.  That is a very low amp draw.

Bill

[xee2]

Xee2:

Yes, nice work.  I remember seeing this a while back.  Instead of the MPSA06, which I think you said will go down to .7 volts, have you tried the new FJD5553 from Fairchild?  It should work to down below .2 volts.  Also, it can handle a lot of power as well.  (within reason)  Your circuit should then probably run for maybe 12 years or so?  I have been playing with them for the past month or so.

Very well done Sir.  That is a very low amp draw.

Bill

I had not heard of anyone getting the FJD5553 to work at 0.2 Vbe. That is an amazing result. Thanks for letting me know about it. I will be looking for your results. According to the data sheet it has a low gain at low power, so it may not be a good choice for low power circuits.

[Pirate88179]

I had not heard of anyone getting the FJD5553 to work at 0.2 Vbe. That is an amazing result. Thanks for letting me know about it. I will be looking for your results. According to the data sheet it has a low gain at low power, so it may not be a good choice for low power circuits.

Well, I don't really have any results ...yet.  The specs say this transistor will switch on down to .21 volts.  It also says it will handle some decent power similar to the TIP 3055's I have been using.  I have constructed a circuit based on the work that you did on the "typical" Kodak type inverter transformers.  I have wired up my circuit according to your pin outs (Thank you for doing all of that and posting it way back when) but I have not yet achieved resonance.  I think this is a resistance problem as I have no real idea of what it will take.  The trimmer I am using goes from 0-200 ohms and evidently, I must need more to get it to work, or, my inverter transformers are a bit different than the 5 pin ones that you used.  (I am still working very hard on this.)  I wish there was a better way to determine the required resistance other than "shooting in the dark" which is the method that I use.  I figured that the 200 ohm range would get me close but....not so.

My idea is to build these modern day "Fuji" style flash boards using better components and only those that we really need.  I came across this recent transistor and the write-ups appeared to be pretty good.  (Possibly not)  I also purchased a bunch of tin can 2N222's and a lot of TIP 3055's but the 3055's saturate at 1 volt and I can get them to run below that but not by very much.  I am very glad that you shared the work that you did on these circuits back then.

Bill

[xee2]

I think this is a resistance problem

Bill,
I do not think it is a resistance problem, 200 ohms should work. I am sure you have tried this, but, the first thing I try when a Joule thief doesn't work is to reverse the leads to one side of the transformer. If that does not work I would suspect something funny with the transformer. If you have a resistance meter able to read fractions of an ohm, you can check to make sure the collector coil has more resistance (more turns) than the base coil.


PS - Your transformers may have a different pin out than the Kodak's that  were used years ago. The Fuji transformers had many different pin outs.