Joule Thief

[sirmikey1]

MrMag,
  The pdf doesn't mention the spikes at all; and I had never realized that this was not well known or understood.  I have heard it mentioned here that the transistor replaces the spark gap ...
Mikey

[jadaro2600]

Can someone explain the concept of parasitic capacitance a bit more ( or at least how this pertains to the joule thief ).

[altrez]

Great job Altrez, and we're gonna catch the guy who left that couch on your lawn.
Speaking of which, it rememinds me of my Joule Thief, well after 800 pages
of "Just make one" I figured I better or I'll just be a back seat scientist ever more.
So after the arrival of my $3 ebay solder iron, here it is....

hahahahahahahahahaha that couch is a classic! i never should of took the plastic off!

Good job on that JT.

-Altrez

[altrez]

MrMag,
  The pdf doesn't mention the spikes at all; and I had never realized that this was not well known or understood.  I have heard it mentioned here that the transistor replaces the spark gap ...
Mikey

Hey Mikey,

I have never read anywhere that the transistor replaces a spark-gap in a JT? Can you please post some links that sounds like a very interesting read! I am not 100% sure but I think the JT is basically just an oscillation circuit that ramps up the low voltage to a very high voltage. At a very low current draw from the battery.

It works with high frequency and high voltage to do some really interesting things I could be totally wrong here so Bill, Jim, Jeanna, xee2 please feel free to correct me!


-Altrez

[stprue]

That's right Altrez and the high frequency changes many things in the circuit equation one of which is the amount of current you need to light a LED.