Re: At what point is electricity dangerous - Scientifically?

Actually, 9 volts is only dangerous if it is placed directly to the exposed heart.

The analogy of water depth mentioned earlier is not correctly used.

The correct analogy is that voltage is like the depth of the water above the port that the water comes out of.

The current is controlled by the depth of the water and by the diameter of the pipe that it is flowing through.

An example of this is if the water is one hundred feet, but the water comes out 9 inches down from the top the current will be low even though the water is 100 feet deep. If a pipe is opened at the bottom of the 100 foot level then the current will be high. If you have a pipe 1 mile high filled with water and with a hole at the very top, the most water that comes out will be a trickle. If you place a hole 9 inches down, this is like a 9 volt battery and is still little more than a trickle. A hole 100 inches down will have a higher flow and can be related to 100 volts. A hole at the bottom of the pipe will be like 60,000 volts and a proportionaly high flow.

However, the danger of electrical shock is not related to being drowned.

It is the current that kills. It kills by stopping the heart.

I personally have been shocked by 3000 volts at 100 to 200 ma. It hurt like #$@^%& but I did not die or even have to go to the hospital. It was not a quirk. The electricity simply went into my thumb and across my hand and out through my little pinky. In the process, it left a path of cooked meat in my hand. Ouch! It took many weeks to heal.

Actually, I have been shocked by million volts before from a generator at a Science museum. So voltage does not kill by itself.

There have been people who have had several amperes passed through parts of their body and lived. People can live through a lightning strike provided the electricity does not stop their heart or seriously damage their nervous system.

Again, an electric signal of 20 ma which passes across the heart can stop it. It can also restart it sometimes. This is what a defibrulator or pacemaker does.

As for how much a zapper puts out, it is normally between 1 on 5 ma and depends on a number of factors, including battery voltage, the actual chip used, the persons skin resistance ( which depends on moisture and salt content of the skin ), and certain advanced circuitry that may be in the zapper.

Some zappers, in order to make the battery last longer ( 10 times as long as some other zappers ), only tell you to replace the battery when it gets below 5 volts. If the chip output is 1 volt below scale ( most chips used by zappers are 2 volts below scale ) then you are only getting 4 volts across the body. If the skin resistance is 5 k-ohm then you are getting only 0.8 ma of current. Way too low.

If you have a brand new alkaline battery of 9.8 volts, using a standard zapper with a standard 555 chip, the output will be 7.8 volts. Across 5 k-ohm skin resistance this results in a 1.6 ma current. Using a salt water solution drops this skin resistance to about 2 k-ohm so that you get roughly 3.9 ma of current which is acceptable. ParaZapper uses a chip that has an output of 0.1 - 0.2 volts below scale. It costs more but with a fresh 9 volt heavy duty battery you get 9.5 volts of output and this means more current.

Notice that all zappers have a 1 k-ohm resistor ( or equivalent ) on the output. If a zapper does not have this then it does not meet Dr. Clarks specification and is not a Clark zapper. This resistor is for safety. It guarantees that with a heavy duty 9 volt battery, the current will never rise above 9.6 ma even it the electrodes are shorted together.

Because of this requirement, the Clark zapper is inherently safe. Electrocution has never happened to any zapper user and there are probably close to a million of them. I checked with the FDA and in the entire existance of the zapper, there has only been 1 incidence report filed. Some older gentleman did not read the instructions before using the zapper and fired off this pacemaker. He did live through it though.


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