Smoothest, and best, store purchased Joule Thief I have seen yet.

[Legalizeshemp420]

With a JT you can easily get over 1500 volts but I will be damned if I know how to even measure that as everything I have would die (I lost my first DMM due to negative ion generators I used to make).

[MileHigh]

You can make an indirect measurement for the peak voltage.  You swap the LED for a low value resistor, say 20 ohms, and look at the peak voltage across the resistor.  That tells you the initial current.  Once you know the initial current then you implicitly know the peak voltage for any resistive load.  What ultimately puts a limit on how high the voltage can go is the parasitic capacitance associated with any high-resistance load and the amount of energy the inductor has available to discharge into the parasitic capacitance.

In plain English, if you see a 7 volt peak when you use a 20-ohm resistor as a load, then if you use a 500-ohm resistor, you will scope a 175-volt peak that is narrower.  You know what the peak voltage is expected to be before you scope it.

MileHigh

[TinselKoala]

Hey Bill, I just posted a video of a quick test of the "Pirate Light"!

http://www.youtube.com/watch?v=f81ZEB_zGVA

(Need shades, the light is so bright!)

[Pirate88179]

Very cool.  I see you got bit by the circuit already, ha ha.  I usually cover the HV outputs with hot glue for insulation but I thought you might want to solder something different someday so I left them bare.  I still get zapped by these even though I am mostly careful, ha ha.

Bill