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Camera Flash capacitor Answered

First off I'll tell you to NOT TOUCH A CHARGED CAMERA CAPACITOR, IT HURTS. I had a disposible film camera that I took apart. How do I discharge it? If I cut one of the leads off the compacitor would it discharge or explode, damage the circuit board? How long would it take to self discharge?


obviously discharge it the two ways to do this are:
shorting the leads by just putting screwdriver on both leads
the second method is to just leave for a while and let it leak (this is a surefire way but takes awhile)
remember always use rubber gloves, no matter what, when using capacitors 

I managed to zap myself twice yesterday with a 330v capacitor out of a fujifilm camera.. burned a tiny hole in my thumb and made all the muscles in my upper body contract. Pretty fun after the fact tho i wouldn't recommend it to anyone.

i really dont like when it catches in ur hand and you have to get it out somehow fast


10 years ago

Ok, If the capacitor lets out a huge spark does that mean it's completely discharged? And it won't get the power back until I hook up a battery, right? Is it safe to take off now.

Yes, but still hold it there for a few more seconds to be sure. When you want to reply to my comment hit the reply at the bottom of my comment.

yay, even if it just sparks do it again, it may still hold a charge because it wasn't fully discharged the first time. THey don't hurt, it's more of a... tingly omg feeling

not true!!! hv capacitors can REGAIN a charge via dielectric memory

very dumbed down, depending on how often the cap was pulsed, it can regain its charge. a safe bet is to place bare wire on both terminals AFTER fully discharging the cap (dielectric memory recharging is not instant). although a screw driver works, high value caps charged at 12 volts can MELT cheap screw driver tips. use a 1mega ohm bleeder resistor connected to the capacitor (not sure anode or cathode) and ground.

I'm pretty sure that to get the effect you're talking about, you need caps that were originally charged to several thousand volts, not merely the several hundred of a typical photoflash cap. Still, better safe than sorry.
My standard procedure for disassembling a camera:
  • "wind" film - there's a wheel that the film will turn to cock the shutter; you can turn it by hand once you've gotten into the film compartment.
  • charge flash. You may have to install a good battery to do this. (Now you know exactly how charge the cap is: fully
  • remove battery.
  • trigger shutter. The flash should go off, MOSTLY discharging the cap.
  • Short cap leads with screwdriver. Twice.
  • at this point, the cap is discharged and should stay that way.
I think I've disassembled about 50 cameras, and not been shocked yet.

your probably right. its more a problem with tesla coil capacitors than anything else. still, it is better safe than sorry. your procedure works very well. also, by first using the flash, you prevent enough charge to ruin the screwdriver.

i found out about this reading up on some hv project or other. ohh, i almost forgot:


are you like this kid, one of my friends. this person has a shocky pen, shocks every on in the class. My firend grabs it and just laughs as you see his hand twitch. Then the battery dies and he goes "awwww"

i used a resistor tho hold it with pliers it gets kinda hot


10 years ago

According to the schematics at Sam's Strobe FAQ, you should be able to discharge the capacitor on most of the disposable camera flash units by jumpering the contacts that go to the shutter; this involves a relatively big resistor, so you don't get big sparks, and it may take a couple minutes to fully discharge. (And note that by the time you've exposed the shutter contacts, you've also exposed the "dangerous" bits.) and some strobes don't have a DC path there at all. I'd still do the screwdriver across the cap bit to make sure!

Touch the ends together with a screwdriver. Make sure you are not touching the metal, and I would recommend wearing gloves