Becoming The Path Of Least Resistance!

Take a medium-large resistor, and connect it across the pins of the cap "for a while" - How long "a while" is will need to be figured based on the value of the cap and the resistor, but a minute or three should be adequate for all except the largest resistor/cap combinations.

And count yourself lucky - Caps can be more dangerous than straight-from-the-plug juice.

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"PopperAndShadow"

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What would you call medium to large 500K to 1M ?

Also I was thinking, If I connected my self to an Earth with a high resistor in between would this not stop me from getting a bitch of a shock.

Thanks.

That would be a reasonable starting point.

That answer would be a resounding "MAYBE".

A "maybe" that I wouldn't count on as far as I can throw an elephant.

Bleed your big caps like those in flash units or power supplies down to zero before doing anything. And once you've bled them down, short them out so they can't bite you with "bounceback". Don't even consider any other method unless you don't care about whether you live or die in the process, and your life insurance is paid up. It doesn't take much to stop your heart if you manage to get a cross-chest discharge to happen. You might get lucky a few times, but sooner or later, the timing is going to be "just wrong", and you'll die waiting for someone to find you and call the ambulance.

Cool thanks, Ill bleed them for a long time, and then short and test with a multimeter. Also Ill disassemble the thing wearing insulated gloves this time.

Thanks alot for the help

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whitelist,

"PopperAndShadow"

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Something like 2K to 5K, 10 watt wirewound, for a few minutes.

That won't help at all.

John

Wow, what kind of voltage and capacitance are we talking about?

Photoflashes run roughly 300 volts typically. Cheap ones store tens of joules, and a really juicy pro flash might run 100 j or so.

Each microfard stores about 1/20 of a joule at 300 volts.

E = 0.5 * C * V^2

John

Go to a local store that processes film, and sweet talk the clerk out of one or more of the disposable camera "empties" that are left after they remove the film. Some nice low Vce xsistors can be gotten that way, plus the cap. Nothing special about it - just (relatively) high voltage. Discharge the cap during disassembly! Getting bitten by the ~300 V is not likely to be a favorite activity. :-)

Ed

You got the shock because you were holding the case, i.e. the electric "ground" for the camera's electronics and touched the high voltage end of the flash strobe capacitor.

That won't really help as the capacitor will still be charged when you start doing any modifications to the camera's electronics.

Yeah, I was recently tinkering with something similar. I had an 820uF cap charging to ~350V (roughly 50J) and dumping it thru a 4 ohm electromagnet coil from a Ford starter solenoid using a TYN612MFP SCR. Pretty good at launching computer case screws across the room. ;-) Lately I've been using that same coil to listen to the stepper motor impulses of my quartz watch, while timing them to the microsecond with a PIC (jitter free even). Problem is my watch has a better crystal than the PIC.

At any rate, AIUI my setup could be discharged from 350V to 9V in right at 15 seconds using a 5K resistor. The OP wouldn't really need to wait for a few minutes, would he?

Better yet, clip the meter across the resistor leads and watch the cap discharge. Be sure to set the meter to a high voltage range to start with. If it looks like the cap voltage is going down too slowly, use a smaller R.

Best regards,

Bob Masta dqatechATdaqartaDOTcom D A Q A R T A Data AcQuisition And Real-Time Analysis

Lytics have a bad habit of recharging themselves from dielectric absorption. If you did the quick discharge to, say, 9 volts, it might well charge back up to some 10's of volts if you removed the resistor at that point. That won't zap you, but you'd still get a nice little spark if you shorted it later. Minutes of discharge will pretty much clean it out.

It would be fun to get a *big* sheet of copperclad (as in *big), drill/cut/etch a low-impedance pattern, and start collecting caps from disposable cameras, and adding them over the years. Around a kilojoule or three, things start to get interesting.

John

Owww...thanks! That gave me an idea for an inductive pickup.

Det var smuk og solrig dag da Don Bruder skrev news:44300883$0$95961$ snipped-for-privacy@news.sonic.net i sci.electronics.basics:

More like a NO WAY. He would have to be sure that he isn't connected to ground anywhere else. Then when he is sure that he isn't connected to ground anywhere, why would he connect himself to ground through a resistor?

To quote the subject:Becoming The Path Of Least Resistance! That path would not be through the resistor, thus he would get zapped when he touch ground somewhere(of course by mistake).

"DecaturTxCowboy"

They're great, and they only cost about $5 brand new. Just be careful when removing the coil from the casing; if you break the inside lead off too short, you're gonna have a real hard time getting some more slack in it.