Joule thief voltages:

El cheapo joule thief setup, with a spare blue LED, a ferrit from an old mainboard coiled with a pair ripped of a 80 pin ide cable (be lucky - one has a colored stripe, 39 other pairs not ;-)

[pic TBD]

here three dso pics with a battery voltage at about 1.2 volt (bright light), 0.6 volt (still lighting) and 0.5 volt (no light):

at about 1.2 volt we have about 35 khz: (please click to enlarge)
the 3.6 or 3.7 volt peak makes a bright light.

1.2volt-l.jpg

at 0.6 volt or so its about 140 khz: (please click to enlarge)
the ~3 volt peaks are good enough to get some light.

0.6volt-l.jpg

and with 0.5 volt there is no light, but it is still oscillating at 200 khz: (please click to enlarge)

0.5volt-l.jpg

about 2.6 volt peaks are left for the led - not enough...


ok, maybe i took the numbers total wrong,
but it was fun playing with the dso ;-)

see the dso 2090 at conrad.de (german site).


anyway, have fun!


• back to bertnase.de


Tue Jul 21 21:43:32 CEST 2009