Did I just narrowly escape electrocution?

[Nobie]

So I'm going through my closet and find my old Minolta camera gear from long, long ago. I'm amazed at my collection of glass, none of which I can use on any of my Nikons. Anyway, I pull out my old flash, a Vivitar 550FD. I instantly decide to go outside this evening and do some light painting on my house and landscaping for fun. I know better than to toss it on my camera's shoe, these old flashes have a much higher trigger voltage and would most likely damage my DSLR. So, I flip the switch on the flash and don't hear the charge...as expected. I pop the old batteries out and yes, also as expected, they leaked. So, I grab some rubbing alcohol and Q-tips and start cleaning. I pop fresh batteries in, still nothing. Ah! the contacts on the battery compartment lid are still rusty despite the cleaning, so I grab my pocket knife and start scraping to bare metal. Try again, presto! I popped off a few test flashes and grabbed my camera and tripod and headed outside.

First attempt, perfect. I had it on manual with 30 sec, did about 8 pops of the flash to paint the house. Looking good, I made a few adjustments with my composition and readied for another go. This time, although I could hear the 4 batteries charging up the flash, nothing was happening when I would hit the ready/test button to fire. I kept pushing, kept flipping through the old flash settings, gave it a few Fonzie's, still nothing. I kept messing with (aka shaking, thumping, pushing, etc.) the flash for about 5 solid minutes with no results...but I could still hear that super high pitched charge going on. As I began to lift the old flash to my face to listen again to the charge, it happened. Just like on those YouTube videos on how to make a disposable camera w/flash into a stun-gun, but to the 9th degree...KAPOWEE!!!! A loud POP! and a burst of blue shot out of every plastic seam of the flash as I dropped it to the ground. All I saw was a blue halo encompassing the entire perimeter of my peripheral vision. I felt a charge all around my upper torso, like a very strong and continual static charge.

Did it just scare me, or did I just narrowly avoid knocking myself out with an unintentional homemade stun-gun?

[candleman]

probably.. i know of someone else who dropped a flash and it was continually sucking battery juice and giving off a high pitch squeal. ..i dont think it ever "popped" like yours but by the sounds of things something funky happened to the capacitor and it decided it couldnt hold anymore juice.

good you werent hurt tho'

[Quo Fan]

Sounds like catastrophic failure of the charge capacitors. Not a whole lot of voltage, but a boat load of current, that is what you felt. And yes, it could have hurt you seriously.

[morts]

Yeah the voltage on the flash isn't much but the current in the caps is obscene and it would seriously mess you up if it made proper contact...

At uni, our sound engineers used to haze one another by charging an amplifier cap and throwing it to someone, shouting "CATCH!"... One of those will fling you across a room if you catch the contacts.

Most flashes that I know of charge the capacitor to about 300 volts. That is enough to kill you, but not likely.

With anything high voltage, if you are holding the circuit in one hand and it shocks you, you're probably pretty safe. If you are holding the circuit in both hands, the electric current passes all the way through your body, and stops your heart.

The big lesson here is to not open or try to repair a flash without fully understanding what you're doing. In your case, it sounds pretty odd...

[Mr Guy]

As stated (and implied) by others, the discharge from a capacitor is likely to cause electrical burns, but not electrocution. Not unlike accidentally touching a car battery terminal and shorting to ground. To stun, the current has to be enough to override nerve impulses in a large chunk of your body, ie, it needs a high voltage (and low amperage). To kill, the current needs to short through heart which only requires a very small amperage to do damage, but it needs the proper path and enough voltage to overcome the skin's resistance. Fortunately, our bodies are built so it's fairly difficult to electrocute yourself without some serious voltage, generally, but unlikely circumstances can result in electrocution with a very small voltage if the amperage is enough.

Luckily, a capacitor isn't going to do that, unless you're wet and very very unlucky. What YOU almost made isn't a stun gun, it's a cattle prod.

[Nobie]

I can only wonder the horror that would have done to my DSLR had I been dumb enough to toss it on the hot shoe.

[OsmosisStudios]

You'd be amazed at the power involved in the capacitor for flashes. I zapped myself with both a disposable camera (hit the circuit board with my finger while the capacitor was charged). That hurt.

Earlier this year I was helping some co-workers disassemble some old Nikon 4100s we had lying around. You know, for, er, "scientific" reasons. I forgot to check the batteries. Sure enough it had charged the capacitor for the flash. I hit something with a screwdriver and felt all my muscles convulsing for a few seconds. I still had heart palpitations for hours afterwards. That was scary.

This is the reason why I won't build a microflash (a flash capable of a very bright, very short duration flash...used for taking photos of bullets and extremely high speed photography). The capacitor used in microflashes stores around 20,000 volts...more than enough to fry me. Even with an electrical engineering degree, I won't touch one.