Jewel Thief Help - Electronic Circuits Projects Diagrams Free

team_nightstalker · 21st September 2007, 12:34 PM

I'm attaching a picture of my board as i can't figure out why it is not working.

ronsimpson · 21st September 2007, 12:59 PM

A little information will help!
What do you want it to do?
Schematic?
Are you trying to light an LED with a 1.5 volt battery?
Transformer? 1:1 windings? Inductance?
That transistor? Is it a transistor?
I can clearly see from the photo that your battery ran down! LOL Help us help you.

ericgibbs · 21st September 2007, 01:14 PM

Quote:

Originally Posted by team_nightstalker

I'm attaching a picture of my board as i can't figure out why it is not working.

hi,
With the Joule Thief its very important that the transformer windings are in the correct sense, else it will not oscillate.

Looking at the pix, it appears you have the conenctions to transistor and LED ok, but I cant check the pin polarity.

ericgibbs · 21st September 2007, 01:16 PM

Quote:

Originally Posted by ronsimpson

A little information will help!
What do you want it to do?
Schematic?
Are you trying to light an LED with a 1.5 volt battery?
Transformer? 1:1 windings? Inductance?
That transistor? Is it a transistor?
I can clearly see from the photo that your battery ran down! LOL Help us help you.

hi Ron,
Its a device called a 'Joule Thief' it runs on a 'flat' battery until it drains all the battery. Drives an LED.

Lotsa Googles

blueroomelectronics · 21st September 2007, 01:24 PM

It's actually called a Joule Thief
http://www.emanator.demon.co.uk/bigclive/joule.htm

team_nightstalker · 21st September 2007, 01:32 PM

i also found this http://www.solarbug.com/whiteled.html
maybe my windings are off? crap man i have wound that thing 6 times now. i'll redo the whole thing and re upload a pic later.

ronsimpson · 21st September 2007, 01:37 PM

OK thanks Eric “Jewel Thief” did not mean anything to me. I should have researched it. Now that I am researching it, my searches lead back to this forum where I am the one in the dark. I draw the schematic (from the proto-board) but why when NightStalker had it.

Now I see it! EPE November 1999. I have those in a pile on the floor.

Hero999 · 21st September 2007, 01:38 PM

The correct spelling is "Joul Thief"

Try swapping the connections to one of the coils.

Also bear in mind that this circuit is designed to power a white LED, not a yellow LED so you might want to think about adding a series resistor with the LED or it might overheat. Yellow LEDs have turn on voltages of around 2.1V and white LEDs have forward voltages of around 3.5V which is quite a large difference.

team_nightstalker · 21st September 2007, 01:52 PM

could it be because i'm using a 1K resistor?

Hero999 · 21st September 2007, 01:58 PM

No, that's the value you're supposed to use!

team_nightstalker · 21st September 2007, 02:00 PM

ok here is the rewire. i do have a white LED as well. even swapped the coil wires a1 with a2. i know i have a1, a2, b1, b2 right.

team_nightstalker · 21st September 2007, 02:02 PM

ok the transistor is a radio crap 3906. that should not be a problem either should it. it's just basically a relay.

ericgibbs · 21st September 2007, 02:04 PM

Quote:

Originally Posted by team_nightstalker

could it be because i'm using a 1K resistor?

hi,
No, a 1K0 is required in the base circuit.

Disconnect the transformer and use an ohm meter to measure the transformer, to ensure that you have not got the windings crossed over.

When its connected, what dc voltages do you measure at the transistor base and collector?

Is the LED ok and the correct way round, if its been connected in reverse it could have died.

Hero999 · 21st September 2007, 02:05 PM

I thought he was talkging about the 1k base resistor.

Have you checked the connectiond between the components using a multimeter?

Breadboard has a nasty habit of failing to make good connections.

EDIT:
Have you checked both the LED and transistor?

The transistor might fail if the LED becomes disconnected and the LED might fail if it's connected backwards.

team_nightstalker · 21st September 2007, 02:09 PM

ok just tried the 3904 NPN and a 2222a NPN as the 3906 is a pnp. man i'm all confused.

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21st September 2007, 12:59 PM	(permalink)
ronsimpson	A little information will help! What do you want it to do? Schematic? Are you trying to light an LED with a 1.5 volt battery? Transformer? 1:1 windings? Inductance? That transistor? Is it a transistor? I can clearly see from the photo that your battery ran down! LOL Help us help you.

21st September 2007, 01:24 PM	(permalink)
blueroomelectronics	It's actually called a Joule Thief http://www.emanator.demon.co.uk/bigclive/joule.htm __________________ Bill Smart Kits build Smart People http://www.blueroomelectronics.com

21st September 2007, 01:32 PM	(permalink)
team_nightstalker	i also found this http://www.solarbug.com/whiteled.html maybe my windings are off? crap man i have wound that thing 6 times now. i'll redo the whole thing and re upload a pic later.

21st September 2007, 01:37 PM	(permalink)
ronsimpson	OK thanks Eric “Jewel Thief” did not mean anything to me. I should have researched it. Now that I am researching it, my searches lead back to this forum where I am the one in the dark. I draw the schematic (from the proto-board) but why when NightStalker had it. Now I see it! EPE November 1999. I have those in a pile on the floor. Last edited by ronsimpson; 21st September 2007 at 01:41 PM.

21st September 2007, 01:38 PM	(permalink)
Hero999	The correct spelling is "Joul Thief" Try swapping the connections to one of the coils. Also bear in mind that this circuit is designed to power a white LED, not a yellow LED so you might want to think about adding a series resistor with the LED or it might overheat. Yellow LEDs have turn on voltages of around 2.1V and white LEDs have forward voltages of around 3.5V which is quite a large difference. __________________ I also post at the following sites: http://www.stop-microsoft.org http://www.heated-debates.com Screen name: Aloone_Jonez

21st September 2007, 01:52 PM	(permalink)
team_nightstalker	could it be because i'm using a 1K resistor?

21st September 2007, 01:58 PM	(permalink)
Hero999	No, that's the value you're supposed to use! __________________ I also post at the following sites: http://www.stop-microsoft.org http://www.heated-debates.com Screen name: Aloone_Jonez

21st September 2007, 02:02 PM	(permalink)
team_nightstalker	ok the transistor is a radio crap 3906. that should not be a problem either should it. it's just basically a relay.

21st September 2007, 02:05 PM	(permalink)
Hero999	I thought he was talkging about the 1k base resistor. Have you checked the connectiond between the components using a multimeter? Breadboard has a nasty habit of failing to make good connections. EDIT: Have you checked both the LED and transistor? The transistor might fail if the LED becomes disconnected and the LED might fail if it's connected backwards. __________________ I also post at the following sites: http://www.stop-microsoft.org http://www.heated-debates.com Screen name: Aloone_Jonez Last edited by Hero999; 21st September 2007 at 02:07 PM.

21st September 2007, 02:09 PM	(permalink)
team_nightstalker	ok just tried the 3904 NPN and a 2222a NPN as the 3906 is a pnp. man i'm all confused.