Joule Thief

[resonanceman]

My motor needs DC.  And at startup I need the voltage for about 2 seconds.  Once up and running, I only need the voltage for milliseconds.  I am believing the JTC may not be capable of drive my motor, at least not yet. 

detrix


I was thinking       if you want to  see if  a JT can run your motor  why not  cheat a little.....
What  did you power your first machines with?

I am thinking  that a small high voltage power supply could be used to charge a cap or something.......  This  little high voltage power supply could then  be turned  off once your motor is up to speed.

gary

[detrix42]

detrix


I was thinking       if you want to  see if  a JT can run your motor  why not  cheat a little.....
What  did you power your first machines with?

I am thinking  that a small high voltage power supply could be used to charge a cap or something.......  This  little high voltage power supply could then  be turned  off once your motor is up to speed.

gary

Hi Gary,  I have gotten a joule thief up to 350+v.  But how to charge up a large cap fast enough has been my issue.  I am trying to get the oscillations of the joule thief into another LARGER transformer.  A friend dropped of lots of electronics junk, and among that, there was several larger transformers.  I tried to get the oscillations of the joule thief into one of them today.  Not happening.  I can take the AA battery and tap on the primary coil, and see a fluctuation in the output/secondary.  But the pulse from a joule thief don't seem to doing anything.  I still have a few ideas to try, tomorrow. 

But getting a large cap charged up by starting with a high voltage power supply, and then turning it off when its up and running sounds interesting.  I have been using a bunch of 9v batteries to get high voltage.  Thanks for your help.  Please keep it coming.

Detrix

[Pirate88179]

@ All:

I have not had much time to experiment lately but, I have been trying to get a new project going and it looks like I will need some advice from you all.

I got a good deal on some very nice solar garden lights ($3.00 US ea.) which have a very nice rechargeable AA battery inside, a really nice solar cell and a photocell to turn the circuit off in the daylight.

They are not that bright but do burn all night long.  So, yes, you guessed it, I decided to take one apart in order to see about using the good old JT circuit to run several larger, brighter leds.

Well, I took it apart and it has a very tiny led.  (clear)  I have never seen one this small.  There is no computer chip or transformer inside, just a few resistors mounted on a small circuit board.  So, I tested the output of the battery at 1.2 volts and then the output at the led and it was 1.1 volts.  Evidently, this small led will light and run on only 1.1 volts and lower.

The only other device inside is the photo diode on/off switch for detecting sunlight.  There is a round blob of dark gray material on the circuit board that covers several traces on the board.  I have scratched this material with a jeweler's screwdriver and, it is hard, but I have no idea what it is or why it is on the board.  It is not a glue as far as I can see and it is not holding anything at all.  This wouldn't be some blob of silicon making a crude type of transistor would it?

I have to leave to go out of town on a job in a few minutes but, when I get back, I will take and post some photos of the project so you can see what I am up against.

The lights do have a cool reflector for the led very similar to my hand crank lantern.  The led shines down from the top and the light is dispersed 360 degrees around out all of the sides from a parabolic type of mirrored reflector.  I think I can fit a small JT inside the case along with 2 super bright large (10mm) leds which will make the output about 10 times as bright as it is now.

I guess I'll just scrap the circuit board and use a JT and the photo diode.  I have been thinking about this for a while but seem to have a mental block on how to wire the JT, photo cell, and the battery.

Photos to come,

Thanks.

Bill

[Pirate88179]

Had a few minutes so here are some photos:

You can see the gray blob in the first photo.  There are no transistors or chips or transformers inside.  This is it.

What do you think?

Bill

[IotaYodi]

This wouldn't be some blob of silicon making a crude type of transistor would it?

Could it be some type of heat sink?