Joule Thief

[gadgetmall]

Hi Guys and Merry Christmas to Each and every one of you . I hope you and yours  get what you want for Christmas .
As for me i am getting this LCF meter after years of wanting one and i will make good use of it to find out why some of my circuits work and some don't . Here is a link for this China Jewel . It can measure Frequency to 500 mhz as well as inductance and capacitance and this will tell exactly how and why several circuits are charging higher than the supply of the modded crossover . There is one other person who has replicated this exactly so i am not alone in this one . http://www.ebay.com/itm/300731799625

this is less than 40 dollars and will be a much needed coil winders tool This is bare Bones and will fit In a small box enclosure i have .

L8r 

Gadget

[drodenbe]

BS2012

If you leave the base lead open which normally would go to the positive terminal and install a resistor of about 1k in series with about a 20k pot and connect them between the base and the positive you have a basic Katcher circuit.  I don't know if you have ever worked with them but they produce a large output.  I lit 200 leds off of the last one I built.  I have never tried with toroid core ,But I will today may be interesting.  By the way I have built a joule thief coil that has been working for a couple of days and it charges the battery and I have a 2600F supercap that it charged up from 1.5 volts to 4.8 volts overnight.  I have an HP3490A 6 digit multimeter that I monitor my circuits. I picked it up second hand I think a must when working with these circuits.  It reads 4 and 5 places right of decimal point.  The coil I wound is a E core configuration with 500t on both primary and secondary.  The cores are separated by 2mm gap.  Pop cycle sticks work great.  On one of the windings I wound a 10 turn coil with #22 wire.  The 500t coil is #24.  I use one winding as joule thief.  If you have two grounds from outside as I do you should run the positive side of the battery to one ground and hook the other to the plus side of the circuit.  I have tried the same hookup only using the negative side but the plus side works better.   I am experimenting with different windings to see if I can improve the charge rate.  Also I want to add that with the gap between the other winding It doesn't load the primary coil.  This is a plus in its self.  Have not had time to check out the possibilities with the second winding.  Well I guess I have spent my two cents.  Have fun playing with circuit if you like. 

[drodenbe]

gadgetmall

I bought one of the LC meters you are talking about.  I have had it for a couple months and it is great.  I have two other different kinds, I bought earlier and I hate them.  won't measure most of what I hook them up to.  But this one is great.  I am so happy with it I am going to give it a new home inside a nice utility box.   

[TinselKoala]

Those meters are so cool.... I just used my Arduino and a few other parts to build a little circuit to measure inductance. A little more work and it becomes the LC and Freq meter too, but for now it's just inductance. It's amazing how versatile the Arduino is. This morning it made my breakfast in the TKSousDuino PID temperature controlled crockpot, and tonight it's measuring my stray inductors, and doing it better than my "ProsKit" LCR meter.

http://www.youtube.com/watch?v=S6N8ys8FiA4

Links to the source of the project and the program sketch are in the video description.

[TinselKoala]

I thought you might like to see a scopeshot of how these meters do their thing.

This is it measuring a 1 milliHenry coil: The top trace is the pulse response from the comparator circuit and the bottom is the stimulus pulse to the coil and its ringing response. The Arduino sends a short pulse and the inductor rings, and the Arduino reads the frequency of the upper trace and then calculates the inductance, according to the known capacitance value of the tank circuit. It's a pretty thing to watch on the scope.