Joule Thief

[innovation_station]

hello all

im in the process of rebuilding a few cam units on a hard board .....  why?

well i want to charge lets say 3 small value caps like 1uf 2uf 3uf   well when they are full they will automatically discharge...

now if i could have the voltage around 90v or so ....  and discharge them to 3 diffrent coils i could have  some powerful style generator

speed is key ... 


you want your caps always ready to fire  so dont store large amounts just little ones released real fast!   

ist!

probally a good idea to have an overflow neon in there too ......  but once setup it will just run.... all on its own as i see it anyways

[timmy1729]

@ timmy1729 

Congratulations on working out where to connect the tube. Great photo. Thanks for posting it. What model camera did the board come from?

You can replace the capacitor with any value, but make sure it has a voltage rating of at least 300 volts. The cap is not needed.

It was a Kodak MAX HQ disposable with a continuous flash. The box didn't say continuous flash specifically, but the back of the camera said it would keep the flash charged for 15 minutes. But, same thing. I would press the shutter button and it would flash and then it would automatically charge again. That made getting the battery out safely quite a challenge 

So, a cap that is smaller than 300 volts would blow up or something? And, a cap would provide no benefit? I'm sure this works like any other disposable, but does anyone know if it is making full use of both transformers? Someone said on here many pages ago that the circuit takes the battery and uses one of the transformers to step it up to a couple hundred volts and charge the cap. Then it further takes the 300+ volts from the cap and steps it up further, using the second transformer and small cap, to a couple thousand volts to flash the tube. I want to see if it is using both transformers.

[gadgetmall]

@jeanna
        Hmm. I guess my post didn't post after Mdmillers about the resistors . If you notice a few pages back where i had the proto board of my earth battery powered Jt is has two Variable resistors and a 10 ohm hard resistor . the two pots are in series with the base of the transistor. they are 200 ohm and 20k so what i do is adjust high resistance and go low until the amount of light just starts to be usable and then measure the total resistance across them to the base . this gives me a hard resistor value to replace them in my particular circuit . you can do the same as everyone transistor and coil etc is different in some ways to me this is the best way to figure out the best circuit gain and tuning for your circuits .Just a suggestion as i have done this with all my jts . I'm in the process of incorporating 555 in this circuit to further My experiments with resonate tuning of the toroid . By the way there is a program called sound scope if you don't have an oscilloscope that uses your sound card's line input . it works very well for measuring frequency  and waveforms and voltage  . I can see the spike and H wave form on my SG circuit and also measure the jt frequency and peak voltage  . It may not be as accurate as a real scope but  close enuff for a free scope !.

[xee2]

@ timmy1729 

The camera charges the large cap to about 300 volts and then when the shutter is pushed the 300 volts is sent to another transformer to power the flash. If you only want 300 volts then the large cap is not needed. The circuit will produce about 300 volts continuously, but it will only produce the higher voltage for the flash for a micro-second and then the large capacitor must be recharged before it can generate the high voltage for the flash again. I do not know how high the voltage going to the flash is, but I suspect it is several thousand volts and may be dangerous.

When capacitors are used at higher voltages than they are rated for they usually will short out, but sometimes they will explode.

[innovation_station]

well i built my power supply

i used a d cell battery a cam unit ...  modded  and a 275vac 1uf cap a rectangular yellow one found inside a microwave ..  looked on the net for info found none .....   go figure ...

any how i can continually short the cap it is always full.... 

but i cant seam to get it to fire on its own....   hummmm

any ideas....

i will post a pic soon of the unit i made ...  i will if i must use relays to switch it but i would like to have it fire on its own  i will then dump this cap to a coil of low self inductance .. and see what comes back or use it to produce magnetic waves in an induction style generator that spinns 

ist!