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Camera flash capacitor

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Spork

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flash capacitor

Hello, I was wondering if anyone could explains (in general) what happens in a camera flash charging circuit?

Basically, I have a disposable camera that I would like to remove the capacitor+charging circuit+ flash from, and I am still trying to understand what happens.

I used to be under the impression that capacitors held XuF at XV (X being generic variable) and ONLY at the specified voltage. I then realized that they can be charged UP TO the labeled Voltage at the capacity specified.

So recently I have believed that the capacitor's voltage is that of the circuit's. If this is so, does the camera use an op-amp (or something) to charge the capacitor up to excess of 100v?

Thank you,
Spork
 

camera flash capacitors

Flashes require relativelyhigh voltages. You typically need a few thousand volts to introduce make the xenon gas conductive. There are many of ways to arrange the step-up circuit, but most configurations contain basic elements like inductors and transistors. Modern flashes tend to use complicated active feedbacks for the purpose..
 

camera flash capacitor

Hmm, it looks like the flash is directly connected to the 330v 180uF cap, but I don't have a great view.

Basically the entire charging circuit is there, I just want to tear it out of the camera, so I have a standalone flash... I was wondering if this is 1) feasable (fairly easy to do) and 2) someone could help to identify which parts I need.

Thanks,
Spork
 

Hi Spork,

Maybe this data sheet will help you figure out what is going on here. Simple flyback transformer charges capacitor, then an IGBT pulse one side of a trigger cap to ground, the pulse from the cap goes into a trigger transformer that excites the lamp to a point of breakdown, then the main cap dumps its energy through the lamp and you have a flash.


Regards

dfullmer
 

    S

    Spork

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the camera uses an up-step converter circuit to transform a sinus/rectangular wave generated around a simple electronic circuit to a much higher voltage (initially AC and then rectified) to charge the capacitor.
The capacitor discharges very quickly on feeding the lamp of the flash
 

    S

    Spork

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Ah, thank you guys. I will try to take the circuit out tomorrow.
 

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