I know the general difference between AC(Home Electric) and DC(Auto Electric), but how come a person on an automotive battery or system can touch the positive side and negative side and nothing happens, but if you touch both the positive(hot) and negative(ground/neutral) wire in a home you get zapped or worst? What is the reason you get zapped in the house but can touch all wires on a car? Are there situations on an car where you can get zapped. Trying to learn more on electrical systems, thanks for the help.
Question on AC vs DC
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A car is 12 volts to 14 volts and a house is 120 volts or more. A spark plug wire will zap you with 20,000 volts or more.
Gotta consider the amperage too man. Not many amps in a spark plug wire, lots in a household electrical wire.
Rather than type for the next 1 1/2 hours I'll just post a link. Also, it's more that current kills and not voltage. AC kills easier because it is alternating direction of positive and negative. DC is a constant and flows only in one direction.
http://www.opamp-electronics.com/tutorials/ohms_law_again_1_03_04.htm
http://www.opamp-electronics.com/tutorials/ohms_law_again_1_03_04.htm
Amperage is the capacity to deliver power, or current. Current is flow of electricity. A car battery can deliver what, 500 amps? But it won't deliver that unless it's "asked" for.
Amps multiplied by volts = watts. Watts are a measure of energy consumed. A 60 watt bulb puts out 60 watts of heat and light, whether it's a 110 bulb drawing half an amp, or a 12 volt light drawing 5.
Volts are measures of potential. In this case, potential refers to the difference between the two poles of the source. The greater the potential, the more the electricity will want to jump the gap between the poles. So you can touch the poles of a car battery and not get shocked. 12 volts won't jump through your skin. But 110 will, and it can easily kill you.
As far as AC versus DC goes, AC is more dangerous. When you get shocked with DC (like a spark plug), it makes your muscles clench. It throws you away. But AC, because the current alternates, actually makes your muscles quiver. If the circuit goes in one hand and another, you can (possibly) jump away. But if it goes in your hand and out your feet, all your muscles are locked in place and you can't move.
Amps multiplied by volts = watts. Watts are a measure of energy consumed. A 60 watt bulb puts out 60 watts of heat and light, whether it's a 110 bulb drawing half an amp, or a 12 volt light drawing 5.
Volts are measures of potential. In this case, potential refers to the difference between the two poles of the source. The greater the potential, the more the electricity will want to jump the gap between the poles. So you can touch the poles of a car battery and not get shocked. 12 volts won't jump through your skin. But 110 will, and it can easily kill you.
As far as AC versus DC goes, AC is more dangerous. When you get shocked with DC (like a spark plug), it makes your muscles clench. It throws you away. But AC, because the current alternates, actually makes your muscles quiver. If the circuit goes in one hand and another, you can (possibly) jump away. But if it goes in your hand and out your feet, all your muscles are locked in place and you can't move.
Consider voltage as pressure (psi) and current as flow (gpm). The voltage in a car battery doesn't have enough pressure to overcome the resistance in your body. Lower that resistance, such as placing a metal wrench between the battery terminals, and current will flow. Increase the pressure, as in 120 volts, and current will flow through a higher resistance. It's that Ohm's Law thing
Yup, your skin for having so much water in it will still resist quite well. Take a 9V battery, touch it to your skin...nothing. Touch the top to your tongue...zappy zappy. The tongue has less resistance due to tissue makeup and much more water.
Car battery has a fair amount of amps but with very low relative voltage. 12V won't overcome the skin for the most part.
If you feel effects is a measure of both the amps(amount of power) and the voltage(force of the power flow). A stun gun has only a few milliamps but voltage that is VERY higher(>30,000V generally). Even with its power source a 9V battery, it will throw you onto the ground because the voltage is so high it can cross through clothing and skin to reach your muscles.
In your car, you are more likely to damage it with its own power(shorting a circuit, overvoltage, etc) than you are to hurt yourself. My uncle has gotten a hit off a spark plug wire and he said it felt like a stun gun. I would imagine the ignition coil would carry quite high voltage as well...
Wall current, although painful, is seldom REALLY harmful to you. I certainly wouldn't want to risk it as an option but I have gotten it a few more times than I care to admit. One good thing about household wiring is that the circuitbreaker will generally trip right away if you were to be shocked and shut down the power to it and hopefully save you. 120V housecurrent for a few seconds may only hurt you, but if like the other fellow mentioned, you can't excape it....you are a crispy critter sadly.
Amps(amount of power) are generally more dangerous.
For example, a guy working on a transformer gets shocked with 20,000V but at high amps. He will likely suffer major burns over his body, organ damage, possibly a heart attack, and generally he isn't gonna "walk it off"
Another person gets 20,000V off a stungun. He will fall to the ground in pain but there will generally be no lingering effects more than perhaps pain in the muscles and shaking or weakness for a few hours. Reports of injuries or fatalities from stun weapons are rare. They happen....but they are rare.
Car battery has a fair amount of amps but with very low relative voltage. 12V won't overcome the skin for the most part.
If you feel effects is a measure of both the amps(amount of power) and the voltage(force of the power flow). A stun gun has only a few milliamps but voltage that is VERY higher(>30,000V generally). Even with its power source a 9V battery, it will throw you onto the ground because the voltage is so high it can cross through clothing and skin to reach your muscles.
In your car, you are more likely to damage it with its own power(shorting a circuit, overvoltage, etc) than you are to hurt yourself. My uncle has gotten a hit off a spark plug wire and he said it felt like a stun gun. I would imagine the ignition coil would carry quite high voltage as well...
Wall current, although painful, is seldom REALLY harmful to you. I certainly wouldn't want to risk it as an option but I have gotten it a few more times than I care to admit. One good thing about household wiring is that the circuitbreaker will generally trip right away if you were to be shocked and shut down the power to it and hopefully save you. 120V housecurrent for a few seconds may only hurt you, but if like the other fellow mentioned, you can't excape it....you are a crispy critter sadly.
Amps(amount of power) are generally more dangerous.
For example, a guy working on a transformer gets shocked with 20,000V but at high amps. He will likely suffer major burns over his body, organ damage, possibly a heart attack, and generally he isn't gonna "walk it off"
Another person gets 20,000V off a stungun. He will fall to the ground in pain but there will generally be no lingering effects more than perhaps pain in the muscles and shaking or weakness for a few hours. Reports of injuries or fatalities from stun weapons are rare. They happen....but they are rare.
Ah, this brings back memories of Physics: E&M. The last three posts are right on. AC causes muscles to tighten and DC doesn't. You only need a couple hundred mA of AC to be killed, DC requires 2-3 times that. This is why when working on AC, you use the one hand rule: only use one hand so if you do get shocked, it goes through your hand and not through your chest (heart).
"AC causes muscles to tighten and DC doesn't."
Sorry but it is just the opposite. Since AC passes through zero volts 60 times a second (in North America) it will cause your muscles to quiver. AC will actually throw you away -- DC hangs on to you.
If you get DC to high enough voltage -- try the 600 to 1500 DC volts of transit systems -- it will do more damage to the human body than the same AC voltage. Neither is one you want to play around with.
I started my utility career making 120/240 volts DC from 13Kv AC. During the years I also worked in railway stations making 600 and 1500 volts DC from the same AC 13Kv voltage. I have operated on AC volts up to 765 Kv. I have been there and done that - and I get the pension check to prove it.
Terry
Sorry but it is just the opposite. Since AC passes through zero volts 60 times a second (in North America) it will cause your muscles to quiver. AC will actually throw you away -- DC hangs on to you.
If you get DC to high enough voltage -- try the 600 to 1500 DC volts of transit systems -- it will do more damage to the human body than the same AC voltage. Neither is one you want to play around with.
I started my utility career making 120/240 volts DC from 13Kv AC. During the years I also worked in railway stations making 600 and 1500 volts DC from the same AC 13Kv voltage. I have operated on AC volts up to 765 Kv. I have been there and done that - and I get the pension check to prove it.
Terry
When I was in the Navy, everything 50 volts or higher was required to be signed as "High Voltage." Skin resistance varies from person to person but on the low end, it is possible to get enough current flow to kill a person with as low as 50 v. This is one of the reasons that microphone phantom power is 48v-it falls below the 50v threshold and is not considered dangerous.
JTK
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No doubt about it Terry. I used to work in an R&D deptartment where we would test large DC powered lube oil pumps for turbine skids. They were field-shunt controlled DC motors. Anywhere from 10-50hp was typical. If you caught a green worm from one of those, you were history.
Joel
Yikes. Lots of misinformation here while others are right. I won't point out which is which, I'll just say it's understandable why cemeteries are full of people who thought they understood electricity.
Wise comments qb.
I was going to mention that my various muscle stimulation devices use DC to contract your muscles. They take in AC and convert it to a modulated DC form.You have control over the freq. of the wave form and the duration of the stim time.
Just incase their might be some on here that do not already know your alternator on your car generates AC and use's diodes to simulat DC. The battery on the car is basicly a huge electrolitic capacitor and is used to filter this dirty simulated DC signal.
Just incase their might be some on here that do not already know your alternator on your car generates AC and use's diodes to simulat DC. The battery on the car is basicly a huge electrolitic capacitor and is used to filter this dirty simulated DC signal.
Edison electrocuted an elephant to prove AC was more dangerous than his DC generators.
This is exactly the kind of answers I was looking for. Makes more sense now. Thanks to all of your for the help. Great link too!
What did Tesla have to say about that?
Edison was a big proponent of the electric chair, since it used AC. He thought people would more likely adapt his "safer" DC than the Dangerous AC being used by Westinghouse. I think he tried to coin the term "Westinghoused" instead of electocuted.
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