high voltage photo flash capacitor charger

[steven2]

in these pictures is the disc shaped flyback transformer i used in the test to charge up a high voltage photo flash capacitor , allso the simple circuit i used, with a neon light ,to indicate the capacitor to be charged, this circuit, well the disc shaped flyback tranformer was driven by the same circuit i allways use to drive my other high voltage flyback transformers, which have the biult in high voltage trippler. the disc shaped flyback transformer i used did not have the biult in high voltage trippler, and even without the capacitor chargeing, and neon circuit ,it will only create tiny arcs to the return . but with the circuit the sound frenquency is high as you can hear it. and the high voltage photo flash capacitor took only around 15 seconds to be charged up, in my experiment, before the neon globe came on. when i shorted out the high voltage photo flash capacitor it made a near deafening pop that rang through my ears for a short time. here are the pictures and details, more will be added when i construct it all into a home made pvc circuit box, the flyback driver circuit that i used is the one posted in the high voltage stuff section and was originally the vortex canon circuit, of which i used part of, and this is nearly the same as the transformer driver circuit.

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[steven2]

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[steven2]

here is the simple circuit i used with this disc shaped flyback transformer, remember the flyback transformer only puts out tiny arcs when driven by the driver circuit, but i cant get over how such a simple circuit, allowed the disc shaped flyback transformer, without a biult in high voltage trippler, to charge up a photo flash capacitor so fast that it made that near defeaning pop when i shorted it out

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[steven2]

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[steven2]

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[audioguru2]

Hi Steven,
Didn't you say that your capacitor is fully charged when the neon bulb lights?
A neon bulb lights with only 85 to 90V.

Aren't you charging the capacitor that is rated at only 330V with the thousands of volts that should come from the flyback transformer?
What will happen to the capacitor if the voltage exceeds 330V?

I will have to find and look at how you connect the camera's capacitor charging circuit to the flyback transformer. Aren't you feeding AC into the flyback transformer?
The photoflash units that I have heard start charging the cap at only a few KHz then the frequency rises as the cap becomes charged and its charging current reduces. Maybe the flyback transformer is inefficient at only a few KHz, in a TV it operates at 15KHz to 16KHz. Also in TVs, a huge current pulse is fed to the flyback transformer which is not available from a little camera circuit.

 

[steven2]

great to hear from you audio guru the disc shaped flyback transformer i used dose not have the biult in high voltage trippler so without that i only get tiny arcs that are so small that i have to be nearly touching the treturn to even see this. now from that tiny arc hv out ive got a 100r resister which runs to one side of the neon rated at 240 volts not 140 like i think mistakenly said and from there it goes to the positive of the photo flash cap under charge, in the return line ive got 2 diodes so this is a bit like a half wave rectifier from there it goes to the 1m resister which goes to the other neon leg so from there it goes to the other capacitor termninal and ive managage to recharge that cap seccessfully , takeing into concideration that all the phased out pocket cameras with biult in flashes ive dismantled it was very comon to find at least one diode in them marked as free although i cant identify it i can replace it with the 1n4007 and it works fine in this cae i used 2 diodes reated at the same voltage but higher current as for the resister to the neon well there pritty comon at times, drawing on the details of the circuit of one camera i pulled to bits so i threw one in to, then as for the neon there rated normally at 90 to 240 volts here so i used that because the arcs of the disc shaped flyback are so tiny it helped in the chargeing process and 15 seconds is not bad concidering it takes normally longer for my ex pocket camerea to charge up to light that neon

 

[steven2]

audio guru the miniute i throw that switch the frenquency of the circuit going by the sound it makes is allready high , the high value resister on one side of the neon which is the same as ive found in most cameras ive pulled to bits works ok , i can try find a timer relay circuit to shout the power off the miniute the neon comes on so as to be as a safety measure to prevent over chargeing but at the time being, i swicth the driver circuit off when that neon comes on, ive allready stared investigateing the idea of converting my single ignition coil driver into a high voltage photo flash capacitor charger, all i need to do is use the same circuit but use a higher value resister to reduce the hv out down to a tiny amount. well although it should be low enougth to not even create the tinyest arc but yet it charges faster.

 

[steven2]

audio guru here is a few picture of a simple photo flash circuit note the 1m resister i used one to the neon, well to one side like the one in the photo, now the diode theres one so i used 2 you probably cant see if , then theres the d965 or75 transister and you have a few more resisters and the 6kv trigger coil and the transformer , i used the disc shape version the flyback transformer my diodes are in the return not hv hv out, but it works and my capacior may be a little over charged as there not suposed to tingle when you put your finger across it but then i dont know why i havent blown that capacitor yet, the voltage rateing for that capacitor maybe they can handle a bit more, than they siad they can as for a safety margine

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[steven2]

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[audioguru2]

Hi Steven,
Don't use your ignition coil driver circuit to charge a capacitor with only a few hundreds of volts rating. A series resistor limits current, not voltage!

The same rule also applies to the neon bulb, it lights with 90V, the series resistor limits its current so that it can be used with up to 240VAC and not have too much current. In the camera, maybe the cap voltage does not go much higher than 90V, so the neon lights to indicate that it is fully charged. What is the voltage rating of the original cap in the camera?

 

[steven2]

audio guru 330 volts rated capacitor isent experimenting wonderfull my neon has 240 volts on it my sieries resister works my idea to try an ignition coil was depending on reduceing that positive hv out down to the level i needed, ive got plenty photo flash caps to blow up in the name of science

 

[steven2]

ill scrap the ignition coil idea and stick with the one ive tested

 

[steven2]

ive half completed another flyback driver circuit to drive that lower voltage output disc shaped flyback transformer, and dispite the seccessfull chargeing of that photo flash capcitor over and over again ,ill be getting parts to make a second one ive got a container full of camera photo flash capacitors and ive tried them out and they all charge up good, the best thing is it works and ,i dont know why they dont blow, if the voltage chargeing them is anywhere near excessive, but i think that they can handle it ok and my whole container of them has survived no problems so ill be constructing it all into a new pvc circuit box when i get the storm water pipes to make them from . a string of diodes from the hv output of a flyback can be used acording to some info i found on useing a flyback transformer to chargeing hv capacitors with but it dosent give you any circuits to do it , so i used bits and peaces of ideas from circuits to come up with this one that worked,

 

[steven2]

the last time i dismantled a photo flash capacitor i found the negative foil to be thicker than the positive foil or electrode so i put my diode chain in the return to the flyback transformer

 

[steven2]

in these pictures is another simple capacitor chargeing circuit i put together with about 5 parts, the 2 diode chain this time i used 2x 1n5404 this time they are rated at 3 amps 400 volts each and i used the same 1m 1/4 watt resister to the neon and on the other side i used the same 100 ohm resister, although the first circuit had 1n5408 diodes in it , this time i dident have any the same left so i tried these ones. i used peaces of a terminal block to secure the diode chain together then i super glued it beneath the lid of a spare circuit box i had, and i allso did the same to the resisters so its all stuck to the bottom of the lid, and i originally ran the input wires and capacitor wires out each end of the box through small holes but i ended up useing these screw terminals instead, as for the neon i dident have any with a 240 volts rateing left so i used a 110 volts one and i inserted it through a hole i drilled in the top ciricuit box lid, and then i secured it with some super glue, now the stick on letterings i put on the top of the box is phv= postitive high voltage input, this is from the disc shaped flyback transformer hv out. the next one is fbr= flyback return this is where the return from the flyback goes to, and nc= capacitor negative, this is where the wire from the high voltage photo flash capacitor negative goes to. and the last one is cp= capacitor positive where the positive wire from the high voltage photo flash capacitor runs to. now i used one of my 12 volts lead acid cell rechargeble battery, so i havent botherd to re measure the voltage in it before i tested it out, after i rigged my flyback driver circuit up to the battery then the flyback, and the rest of the wires to the circuit i then switched it on . this time the neon came on strait away and in the few seconds say 4 to turn it off the neon got brighter as if the capacitor charged up in the 4-5 seconds i then shorted the capacitor out useing a screw driver to find out. and it was, as i got the big pop as usual, so this charges up even faster in a few seconds i couldent beleave it at first but when i tried to time it, the second handle on my watch hadent even reached to the 5 seconds yet, i geuss it took the extra second to turn it off

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[steven2]

unlike a pocket camera with a biult in flash as you switch it on you can hear that high pitch sound inside the camera get higher as the capacitor is chargeing up, well in this case the miniute i turn the driver circuit on its allready high pitch so i think it may be chargeing up at a higher frequency,

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[steven2]

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[steven2]

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