Author Topic: High volts, low amps  (Read 14413 times)

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Offline shane_95

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High volts, low amps
« on: July 09, 2012, 02:54:22 am »
Is there a way to get high volts and very low amps?
I want to have a bit of fun with high voltage but I want low amps so I don't kill my self.
 

Offline SeanB

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Re: High volts, low amps
« Reply #1 on: July 09, 2012, 02:58:14 am »
Plasma globe. Can bite though.
 

Offline shane_95

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Re: High volts, low amps
« Reply #2 on: July 09, 2012, 03:08:39 am »
Is that one of those things that has the glass do e and when you put your and on it, purple arcs go nuts
 

Offline SeanB

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Re: High volts, low amps
« Reply #3 on: July 09, 2012, 03:17:03 am »
That is right, buy a cheap USB or 12V powered one, and leave the globe on, it will act as a high voltage resistor.  If you remove the globe the output is going to hurt.
 

Offline shane_95

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Re: High volts, low amps
« Reply #4 on: July 09, 2012, 03:20:51 am »
I want to some how make the circuit, I have a 240v to 9V 1A. Is there so,e how to step,up the volts and lower the amps?
 

Online Simon

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Re: High volts, low amps
« Reply #5 on: July 09, 2012, 04:10:47 am »
hm, we seem to have a plague of people wanting to kill themselves this weekend. If last week you were asking "how to charge a capacitor" and now you want to play with high voltages. 50V kills, 30mA kills ! if anything buy something pre-built.
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Offline shane_95

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Re: High volts, low amps
« Reply #6 on: July 09, 2012, 04:36:47 am »
Shit, wow. It doesn't take much, some of the led's I have draw enough mA to kill me 3 times, then with my bad heart, even more  :-\
 

Offline T4P

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Re: High volts, low amps
« Reply #7 on: July 09, 2012, 04:42:22 am »
Shit, wow. It doesn't take much, some of the led's I have draw enough mA to kill me 3 times, then with my bad heart, even more  :-\

Er, no. It seems you haven't been reading theory.
Unless the frikin' led's are drawing 200V, no.

hm, we seem to have a plague of people wanting to kill themselves this weekend. If last week you were asking "how to charge a capacitor" and now you want to play with high voltages. 50V kills, 30mA kills ! if anything buy something pre-built.
at wet skin resistances are about 10k which means about 5mA at 50V ... not too much of a shock
Dry skin resistances mean about 1meg maybe, 1meg at 200V is 0.2mA
now ... wet is where it gets bloody dangerous at 20mA
 

Online Simon

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Re: High volts, low amps
« Reply #8 on: July 09, 2012, 04:49:53 am »
The theory goes like this: the human body is considered to have a resistance of 1K (usually with regards to mains voltage AND frequency). it takes 40-50mA to kill you stone dead. 1K x 50mA = 50V !!!.

If you want to play with high voltage make sure you actually know what you are doing because we can't help after your dead and it only takes one mistake. I have had an RCD save my life before and they cut at 30mA and believe me it hurt and left me very shocked.
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Offline shane_95

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Re: High volts, low amps
« Reply #9 on: July 09, 2012, 04:55:21 am »
I'm now confused, I'm going to bed, it's 5 am here
 

Offline T4P

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Re: High volts, low amps
« Reply #10 on: July 09, 2012, 04:56:05 am »
The theory goes like this: the human body is considered to have a resistance of 1K (usually with regards to mains voltage AND frequency). it takes 40-50mA to kill you stone dead. 1K x 50mA = 50V !!!.

If you want to play with high voltage make sure you actually know what you are doing because we can't help after your dead and it only takes one mistake. I have had an RCD save my life before and they cut at 30mA and believe me it hurt and left me very shocked.

OH right, didn't know that it can drop to 1k with frequency but i still think you mean WET
 

Online Simon

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Re: High volts, low amps
« Reply #11 on: July 09, 2012, 05:14:22 am »
I'm not sure and it's only a guideline, babies will be less, old people more, no one is the same but from memory 1K is the figure used in explaining what voltage you need to kill yourself with if your really intent on doing so like some people here.

Frequency has other effects, I hear tell that at higher frequencies you get off more lightly as the current does not go through you but over your skin (so not through your heart) but I'm no expert and I don't deal higher than mains and treat it will more respect than any god !
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Offline Spikee

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Re: High volts, low amps
« Reply #12 on: July 09, 2012, 05:14:39 am »
240v ac and 380V ac is not that bad , it tickels ^^ .

Use an 555 timer + mosfet + ignition coil + dc source
Up to 3 Kv verry low current. nice sparks and won't kill you to fast ;) .

TheSignalPath has an video about it. I did it myself , it does not hurt.
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Online Simon

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Re: High volts, low amps
« Reply #13 on: July 09, 2012, 05:25:53 am »
240v ac and 380V ac is not that bad , it tickels ^^ .


You are very wrong ! 240V kills ! and you are talking to a beginner here. Indeed the ignition coil project is far safer (at your own risk)
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Offline G7PSK

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Re: High volts, low amps
« Reply #14 on: July 09, 2012, 05:40:43 am »
240v ac and 380V ac is not that bad , it tickels ^^ .

Use an 555 timer + mosfet + ignition coil + dc source
Up to 3 Kv verry low current. nice sparks and won't kill you to fast ;) .

TheSignalPath has an video about it. I did it myself , it does not hurt.

You are wrong there, 240 volts off the mains is a very nasty buzzing sensation 415 feels about ten times worse and throws you across the room, I know this from first hand experience. Nine thousand volts at high frequency makes you feel as if the bones in your hand have been ripped out and then put back again, well that's the best i can explain the experience. i got that when I was setting up a mains operated electric cattle fence and when I went out to test I was walking and talkin at the same time and walked right into the fence at the point where the feed came, Not as bad as a friend of mine having set up his sheep fence he got called short and forgot that the fence ran just where he was having a piss, He jumped so high that it must be an Olympic record.
 

Online Monkeh

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Re: High volts, low amps
« Reply #15 on: July 09, 2012, 05:59:54 am »
240VAC is, if you'll pardon the pun, quite shocking. And fully capable of killing you very easily. Been there, nearly done that, will not be repeating the experience for fun.

415VAC sucks horribly and can kill you if you look at it funny. It's far more dangerous than 240V. There's a very good reason you don't place two socket outlets on different phases next to each other.

340VDC (a charged cap from 240VAC) feels like you're being stabbed. With red-hot sowing needles. Don't play with capacitors.

Do not play with high voltages unless you know exactly what you're doing and have at least one person on hand who not only knows what they're doing, but knows CPR.
 

Offline M. András

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Re: High volts, low amps
« Reply #16 on: July 09, 2012, 06:04:32 am »
240v ac and 380V ac is not that bad , it tickels ^^ .


You are very wrong ! 240V kills ! and you are talking to a beginner here. Indeed the ignition coil project is far safer (at your own risk)
i accidentaly touched the wrong end of a live 230V ac switch with 1 hand 2 fingers, it feels like hundreds of little bugs+shaking in the same time, and here i am 10 years later, i would not poke in a box with blindly again thats for sure
« Last Edit: July 09, 2012, 06:07:57 am by M. András »
 

Offline grumpydoc

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Re: High volts, low amps
« Reply #17 on: July 09, 2012, 07:31:45 am »
Like many (most?) people on the forum I've had a few 230V AC or couple-of-hundred volt DC shocks and lived to tell the tale. Once, in my 20's I remember feeling quite pleased that I'd fixed an old valve amp without zapping myself. Finishing off I noticed that the mains switch was loose so reached in to tighten the retaining nut......

It wasn't switched on or plugged in so I think it was one of the paper caps but it hurt like hell.

Now I'm a bit older and a bit more cautious I realise that each shock was a lapse in concentration that could have killed me - it takes very little energy to induce ventricular fibrillation if it hits the heart just right.

In cardiothoracic theatre they use tiny little paddles and one or two Joule shocks to defibrillate directly on the heart - compare that with the 150-200J energies that external defibrillators use. The bottom line is that you can affect the heart's electrical activity with just a few 10's of volts and a few 10's of milliamps in the right (wrong?) circumstances. Much of the time dry skin, imperfect contact and a current path away from the heart limit the damage but do you really want your life to depend on that much luck?

Don't fuck with electricity, small amounts can kill and large amounts can kill with a vengeance.
 
 

Offline Spikee

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Re: High volts, low amps
« Reply #18 on: July 09, 2012, 08:01:15 am »
One time my hand was on a conductor and my other hand on the gnd of my moped running stationary around 6000rpm.
The voltage was around 10Kv if i remember correctly. I was the conductor for a few seconds. It all went trough a big blood vein in my arm. The vein was all swelled up and red for a few days and my hand was also num for a few days. I felt the pulsing in my hart but i survived ...

now i'm thinking i had some hart arrhythmic problems at random times a few weeks later :X , now i just realize why ...

So ... i guess don't don't any of the things i just described.

yay i'm still alive =)
« Last Edit: July 09, 2012, 08:06:37 am by Spikee »
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Offline Chopsticks

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Re: High volts, low amps
« Reply #19 on: July 09, 2012, 10:58:55 am »
G7PSK,
a cattle fence wont kill you because it's designed not to, from memory the international max voltage is 10,000v on an electric fences but they are very low amperage therefor it'll 'zap' you as it pulses but wont kill you
 

Online Psi

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Re: High volts, low amps
« Reply #20 on: July 09, 2012, 03:25:08 pm »
Can we stop arguing and agree that over 50V  *might* kill if the current is over 20mA.

Electric shocks are not something where you can point and say "That will kill you stone dead" or "That's safe"

People out at sea have died from 48V due to the salt water decreasing their skin resistance. And people have survived a direct lightning strike to the head.

It's not something you can label as either lethal or safe because there are so many factors
- Everyone has a different skin resistance
- The resistance in the path to earth when you receive a shock varies depending on the situation.
- The path the current decided to take through your body isn't predicable
- The skin effect (if the frequency is high).
- The condition of your heart
- The time you may/maynot be in contact with the voltage.
I could go on...

So basically.. No one is ever going to recommend you play with high voltage!

If you have a weak heart don't play with high voltage at all.
If you're healthy and insist on playing with it then a car ignition transformer is a relatively safe place to start.
(that's not to say a bizarre/freak encounter with an ignition transformer couldn't kill someone, it's just highly unlikely, statistically speaking)
« Last Edit: July 09, 2012, 03:37:06 pm by Psi »
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Offline amyk

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Re: High volts, low amps
« Reply #21 on: July 09, 2012, 05:24:47 pm »
240v ac and 380V ac is not that bad , it tickels ^^ .


You are very wrong ! 240V kills ! and you are talking to a beginner here. Indeed the ignition coil project is far safer (at your own risk)
i accidentaly touched the wrong end of a live 230V ac switch with 1 hand 2 fingers, it feels like hundreds of little bugs+shaking in the same time, and here i am 10 years later, i would not poke in a box with blindly again thats for sure
You're still alive because the current didn't go through your heart.

When working with high voltage that's the main thing to remember: Don't get in a situation where the current could go through critical parts of your body like heart and brain.

...and if you want to play with "safe" high voltage (at least to humans), try out those experiments that involve static electricity. Those can produce voltages in the 15-20kV range. Just stay away from anything flammable.
 

Offline G7PSK

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Re: High volts, low amps
« Reply #22 on: July 09, 2012, 05:36:43 pm »
G7PSK,
a cattle fence wont kill you because it's designed not to, from memory the international max voltage is 10,000v on an electric fences but they are very low amperage therefor it'll 'zap' you as it pulses but wont kill you
I never said it would kill, In the UK the pulse must be kept below 15 joules and as it is HF you have the skin affect, all I said was that it is painful by trying to describe what it felt like to get such a shock, I know many people who test their fence by grabbing it, not something I would do as I cannot stand the horrible sensation.
 

Online vk6zgo

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Re: High volts, low amps
« Reply #23 on: July 09, 2012, 06:09:47 pm »
Ohm's Law always applies in these situations.
Any voltage/current source looks like a perfect voltage source with an internal resistance.
The 240 volt mains supply has a very low internal resistance,so can source a great deal of current .

If you are across the mains,the circuit consists of  V( supp) which is  the perfect source, in series with R( int) & R (you).

In the Mains case R(int) is sufficiently low that it can be ignored, so the total current is very close to  I= V(supp)/R (you)!!
For 240 volts,that is effectively 240/R(you).

In most really high voltage power supplies that Electronics people play with,R(int) is no longer negligible,so any attempt to draw enough current to kill you causes the output terminal voltage to fall to a low value,limiting the possible current.
It will still "bite" though!

WARNING! WARNING! Will Robinson!!

(1)Large capacitors may be charged to high voltages in some circuitry.
The internal resistance of capacitors is very low,so they can deliver a dangerous shock,both when the device is operating,& immediately after turn off!!!


(2)My comments about high voltage power supplies earlier,DO NOT apply to the power supplies commonly used for tube type Radio RF Power Amplifiers.
These may  be intended to supply 2kV or more,at several  Amps to a power Vacuum tube.
To do this,they need a very low value of  R (int).
From our above discussion,you can see where that leaves you! :o :o :o :o
 

Offline Wilkins

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Re: High volts, low amps
« Reply #24 on: July 10, 2012, 09:51:49 pm »
If you are a beginner, do NOT open up mains powered equipment, do NOT play with mains voltages (plugs into the wall), YOU COULD DIE.

You need to study up on your electronics theory, you have to do a bit of maths but it is fun and easy, don't skip the maths.
 


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