Joule Thief

[kooler]

hello mikey
'' if you will look.. it is backwards '' THE TRANSISTOR IS BACKWARDS ..
all this circuit has is b to e action...
if this looks like a chilliqueen circuit to you then show me a chilliqueen circuit that will light 9 leds bright on just 1.5ma
everyone is like oh.. the chilliqueen circuit.. there is a reason the transistor runs hot in his circuit.. cause it will suck 200-300 ma.. if you let it.. and then when you get the pull down to 5ma it sits there and does nothing..
if you want a jt to run.. on nothing.. use this transistor.. mps2222a
maybe i should just stick with testing circuits and not talking..

robbie

[sirmikey1]

Robbie,
  Sorry to rattle you, was not my intention.  "Is this one still spiking?"
Mikey   

[xee2]

@ kooler

use this transistor.. mps2222a

If you can get some BC337-40 transistors I suspect they will work even better than the mps2222A.

[kooler]

xee2
i just went back and checked the emitter for bemf and the scope doesn't show it but it will light 5 leds.. so the secondary does alot better..
maybe i should send this scope off to get it check.. i may damaged it trying to check my cap discharge circuit..

guruji
i have just got the negative of the battery running thru the coil and the transistor backwards.. and the base has the biggest spikes and the collector has negative pulses going to the positive side of the battery..
but i think something is up with my scope it reads 21 khz not hooked up.. i've read the book 5-6 times.. theres another way to hook this circuit up
so i will keep everyone posted

[altrez]

@all

On a standard JT circuit whats the best way to check for back emf?

Thanks!