Joule Thief

[TheNOP]

  I keep getting 1.2 amps no matter where/how I measure, and on both the Fuji and the toroid it is all the same.

from the description you give it seem to be the right way to measure current.
one prob on + side of the battery the other probe where the battery + side was connected.
+ side of battery not connected to anything else then the prob.

maybe it is what you see, your jt drawing all of what your battery can give.
but that would mean you have a short circuit at all time...


but just to be sure.
your meter is on amps function, on what scale ?

try the resistor way.
put a 1 ~ 10 ohms resistor, measure it to know the exact value, where you were connecting your meter.
measure the voltage at the resistor, probes on both side of the resistor.
I = V/R, this should give you an approximation

[gadgetmall]

morning . vant(HUH?) Oh Can't  sleep heres a look at My boards and lights again . I love em . I remember when these didn't   get  4 hours max  and would eat a battery before breakfast .... Now 12 hours  . Yo u gotta love it cause it is so useful around here especially when the lights go off (Middle of rural area ). lots of power outs and baby is scared of the dark No more . She helped me wind a coil today and soldered a Jt up for her third one now . She sleeps with them  7 and Cute as can be awww ,,
@ Jeanna NIce Work . I still say i got it Close with 100 secondary .30 primary  and 68pf with two  20 k vr's and 430 -480 ohm resistor  total ma 4 leds .81 ma .
I still have your  JT running strong for almost 2 weeks on the same battery . I am Proud of  IT they are your work and i sleep with them Next to My Bed .  .HEHE.

some more pics Of FUGI >< . schematic DONE . Peace to all .

[TheNOP]

@MK1

on the mag amp there are 3 coils
1 is the input source (AC)
2 is the control, the signal DC. a bit like the base of a transistor.
3  is the output (AC)

the output is not only related to the turns ratio of the 3 coils, it is also in fonction of the input (coils 1) and the signal (control coils 2) volts/amps feed to them.

at least this is true for mag amp amplifier gain circuit.

[gadgetmall]

@ All:

For what it is worth all of my Fuji Transitors are D1960's like IST's are.  The T-9A transformer is also on all of them.  Could we not just look up the specs on a T-9A online somewhere to see wire sizes and windings?  I am sure Fuji did not build this transformer but bought a boatload of them off someone's shelf that makes it as a standard item.

@ IST:

Thanks.  You are right, it may be the same a slicing my ferrite.  I guess I just like the challenge.

@ All:

For some reason (ignorance probably) I can not get a handle on measuring amps (mA's) on any of my circuits.  Yes, the books all say as many of you have said, measure amps in series, volts in parallel.  Fine, I get that.  What I don't get is how to do that?  Every time I attempt this, it does not show the draw of the circuit, it shows the amps available to be drawn upon in the battery.  No matter which circuit I use, or how many leds I am running, the measurement is the exact same as the battery alone.  So, obviously I am not doing it correctly.

To put the meter into the circuit like the books say, the circuit has to flow through the meter right?  So, I take the red probe of my meter and insert it into my breadboard just after where the battery plugs in on the + side, and then take my black probe and plug that to where the power jumper would normally go to the + side of my circuit and....it is the same as the battery.  I did it on the - side and got same results.  So, can someone please give me some simple instructions on how to do this properly?  I keep getting 1.2 amps no matter where/how I measure, and on both the Fuji and the toroid it is all the same.  Once I learn this then I can join in and see what mA's my circuits are pulling now.  I really appreciate the help, thank you in advance.

Bill

Hi Bill . I just set My meter on the highest ma setting  mine is 2000ma . one the fugi i leave the battery in but on the back soring clip holding the back i spring it back with a probe and put the other one on the back of the battery still in the holder with the plus of the battery touching its contact . . I was getting 1900 ma before i modded it . Now .81 ma  a fraction ..

[xee2]

@ jenna

I replaced my 1,000 pF base cap with 10,000 pF and performance was about the same but not quite as good. So for me, it looks like I should not go higher than 1,000 pF.

Thanks for the link to the article. It was interesting that he was using base caps.