Joule Thief

[dasimpson]

Check your transformer theory again.

With a step-up you increase the voltage, and decrease the current. The opposite is true when you step-down. So you are back to where you started (high voltage, low current), minus losses.

.99

not from what i read from what i read if you put 100 volts 100 ma into a transformer you can take 10 volts out at 10 amps or somthing was told the theory a long time ago so can not ecatly remember

i was reading part of it here http://www.allaboutcircuits.com/worksheets/trans1.html also here http://www.allaboutcircuits.com/vol_2/chpt_9/2.html

[poynt99]

...from what i read if you put 100 volts 100 ma into a transformer you can take 10 volts out at 10 amps or somthing

It would be more like 10V and 1A out, not 10A, but that is essentially what I am saying as well. Go back and read my post again...carefully.

.99

[dasimpson]

It would be more like 10V and 1A out, not 10A, but that is essentially what I am saying as well. Go back and read my post again...carefully.

.99

yes but that why you use a step down transformer after the step up one

[dasimpson]

It would be more like 10V and 1A out, not 10A, but that is essentially what I am saying as well. Go back and read my post again...carefully.

.99

yeah thoght i was out on the numbers but was giving an example
but what we know of step down it that it will take the high voltage low current to low voltage but high current now we can mess with what we drop it down to so fit are needs not saying it will work but it is an idea when i get to cable modem psu i can test this

[dasimpson]

im just about to put an order in for some transister and i was just woundering what would be the best
the ideal ones would be work from very low voltage and use very little current

so far the choice is
2n2222
2n2222a
2n3904
bc549