Sorry but i got a question why there should be a high voltage like 200V , while i can get 2mA using 10V/5k..

 

I think the 200V was a joke. Nevertheless, you still haven't said clearly what you are trying to do or why. John

 

Almost certainly the current from a 9v battery across dry skin will be imperceptible, therefore the current is <1 mA. Even with skin wetted with salt water you probably won't feel anything.

A doorbell transformer with diode and capacitor will give you 40vdc, the phone line with no ringing signal will give you ~50vdc (and that I can usually feel) and line voltage will peak at 170v.

If you know how high the skin resistance will be for dry, calloused skin then you can adjust the current source compliance accordingly.
I don't think 100v would guarantee 2mA into dry skin but I've never tried it. As long as it's a current source you could go even higher with the open circuit voltage.

BTW, there are probably patents on the waveforms and the machines used to stimulate muscles. I'd be a little careful with this project.

 

I think the 200V was a joke. Nevertheless, you still haven't said clearly what you are trying to do or why. John

A friend who is a doctor of anesthsia , asked me if i can make this device or not which he uses to locate the nerve , he said i've to supply the body current about 2mA , and he will use an injection then he will hit the muscle and it will contract hence he can put anesthsia to that nurve .. that's the story .

 

Are there no regulations in Cairo about medical grade devices? I'd worry a little if my doctor wanted to hook me up with a wet sponge and car battery.

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I don't think 200V was a joke, as Willbe said you need a much higher voltage to get a shock, with dry skin I can't even feel voltages as high as 70VDC and the lowest voltage I've had a tingle from is 30VAC (which has a similar shocking capacity as 70VDC) but I had wet hands so it was my fault. I would go even higher than 200VDC, I'd suggest even 500V again as long as the current is limited it's perfectly safe.

I wouldn't recommend building this thing for anything other than educational purposes and would strongly discourage you from allowing it to be used on patients.

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Cell damage on a molecular level could take 20 years to show up, probably as a cancer.
Speaking of electric currents, I'm also wondering when "the chickens will come home to roost" with all this cell phone usage; half the field energy goes into the user's head.
Some think that there is no damage if no tissue heating can be detected; currently this detectible level is 1/1000 °C. Others say no level of RF is safe.

I think the human body can be modelled as a voltage-dependent resistor, with a low of 300Ω (an electric chair pulling 8A at 2400 vac).
There is a breakpoint at 600v, at which point the skin is punctured and so you lose the protective benefit of skin resistance.

 

I don't see what the RF debate has got to do with this?

Unless the RF causes heating there is no scientific edvidence to indicate that it can cause tissue damage. The only thing that makes RF any more dangerous than infrared radiation is that it's more penetrating and rases the temperature of the internal organs and not just the skin.

To cause cancer the DNA of cells has to become corrupted, there are two main ways of doing this: chemicals can react with the DNA and corrupt it or ionising radiation can knock out electrons in the DNA causing reactions which damage the DNA. RF radiation is too lower energy to cause any chemical reactions, therefore is chemically inert.

The only way RF can damage cells is by heating them, most of the body can withstand fairly large changes in temperature and a large amount of RF energy would need to be absorbed to cause any damage. The only sensiitive areas of the body are the brain an genitals which are more easilly affected by small changes in temperature.

I think the problem is that most people don't understand the effects of RF radiation on the body and they fear the unkonwn.

EDIT:
I think I can see your point you're talking about safety.

Well there is evidence that repeated electric shocks can damage nerve cells but I can't find it on Wikipedia even though I've read it before.

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