Joule Thief

[TheNOP]

NOP,

It does matter how you connect the bridge to the circuit. AC has to go to the ~ ~ pins and the + - Are the DC output. If you look at how the diodes are connected you will see what I mean.
The two AC connections have the diodes positioned 1 with the anode and the other with diode. The DC side have the two diodes connected anode/anode and cathode/cathode.
So, if you connect AC to the DC terminal there will be no flow through the rectifier during 1/2 of the cycle.

Tim

oops 
you are right.

[Mk1]

@jeanna

Sorry you think you waist your time but , there is no way to tell the drawing is bad ? I will test first since i cant get the data to tell from here what you are doing ?

So i guess i will have to make one other toroid mk2 and test my self , and i will ! And i will keep you posted on the schematics .

@all

http://www.youtube.com/watch?v=Ru8YQ6HUwbU&NR=1  Important because if its true this is a jt !

[jeanna]

@ jeanna

   I do not understand this. The voltage should be between the + and - outputs (with meter set to DC) or between the two AC inputs (with meter set to AC).

If one lead of voltmeter is on the + output and you are getting 37 volts, where is the other lead of the voltmeter connected?  It should be connected to the - output.

Hi xee2,
Sorry, I missed your post earlier,

I don't know if my reply to Jesus answered your question.

There are too many wires to do what you are talking about. MK1 said there was something 'special' about this schematic. Except for being incorrect, I am not sure how special it is. FYI Jesus posted a schematic a few pages back. Jim just added another.

This is a diamond shaped hand made bridge. I pinched a probe onto one of the endpoints and the other probe onto the wire that is supposed to be connected to that point.

This way, there is still a connection of sorts, but with the meter "in between" the parts that should be connected. This should tell me what is happening volt-wise at that connection place.

The problem with the schematic is that there is nothing that comes of the toroid no output. There is a continuous loop from battery jt driven coils around in a loop. The only place where a load is indicated is on that upper ac leg on its way back to the coil.

Except the drawing has the arrow going the wrong way.

I have been trying to get an answer that could shed light on the fact that even though I got 108 volts on the scope - real ones this time- I was unable to light the string of leds that runs on 110v. It should run on way less than 110. The lights should be on but very dim way down to a very low voltage. This is 70 leds. It says it is a series connection, so, I guess it is either strongly protected by being undervoltage, or 2 parallel strings each 35 leds in series. Either way, it should light and it does not. My battery draw is well over 25mA and as far as all my other work shows, this should be plenty.

I am ready to turn a different way.

If you have any ideas about why I am not able to light those lights, please let me know.

as always, thanks for your help,

jeanna

[Mk1]

There are too many wires to do what you are talking about. MK1 said there was something 'special' about this schematic. Except for being incorrect, I am not sure how special it is. FYI Jesus posted a schematic a few pages back. Jim just added another.

This is a diamond shaped hand made bridge. I pinched a probe onto one of the endpoints and the other probe onto the wire that is supposed to be connected to that point.

This way, there is still a connection of sorts, but with the meter "in between" the parts that should be connected. This should tell me what is happening volt-wise at that connection place.

The problem with the schematic is that there is nothing that comes of the toroid no output. There is a continuous loop from battery jt driven coils around in a loop. The only place where a load is indicated is on that upper ac leg on its way back to the coil.

Except the drawing has the arrow going the wrong way.

Jeanna, if the second pair is connected the wrong way around it will cancel the output same thing happen when you connect the coils together, now the bridge going the wrong way ? Your bridge or the picture ?
Anyway i am almost done on a mk3 toroid , i will run some test and we will see.

Mark

[electricme]

@ Jeanna,

OK. I think by sitting back here I have managed to see where both of you are at with this bridge diode, which is driving you both up the wall.

I think the problen is this, Jeanna knows the way the bridge works, but, dosent understand that the bridge diode can be configured to make it work in a different manner as she currently understands it.

Jeanna, you are not wrong in your thinking about this, as you know there are 4 internal diodes in a bridge arrangement.
But, did you know it is not the rule to use all the diodes, in the bridge configuration?

For instance there are times where a bridge diode can be used as a single diode, the others are ignored, (why? perhapse a single diode wasnt avaliable) or 2 of the diodes can be used, the others are ignored, or three diodes can be used and the single diode can be ignored.

If I break open a simple battery charger, I often see a wire leading off from the bridge up to the PCB board, this is supplying half wave rectifying current to the electronics to turn on the yellow LED.
Most battery chargers supply a pulse or half wave charge to the battery, espicially if it is switchable between 6v and 12v

It just depends on the circuit designer, and that such a "simple" diode arrangement" can cause so much confusion.

If the circuit in question was re-drawn using indiscreet diodes, I think you would have no problems in understanding it.
I hoped I was able to shed some light on this for you Jeanna.

jim

@Bill,
Congrats with winning that oscillope, everyone here is going to beat a parth to your front door ha ha ha. I'll bring my "big" bag, it'l fit nice n snugg, lol. Seriously, the Tetronics range of scopes are excellent, ask the fellow you got it from for some quick tips on setting it up.

jim