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Thread: Electrical charges, people, and touch-lamps

  1. #1 Electrical charges, people, and touch-lamps 
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    I have a bunch of questions regarding electrical charges and people:

    1. Does charge require a closed circuit in order to move?

    2. (relates to 1) When you shock someone, I assume this is charge moving from one person to the other. What basic circuit would be at work here? Where is the charge going? To ground?

    3. I read that touch lamps generally work because they have a charge, you touch them and some charge moves from the lamp to you, and the lamp registers this. What basic circuit would be at work here (regarding the charges, not the lamp's inner workings)? Where is the charge going? To ground?

    Thanks!


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  3. #2  
    Forum Senior anand_kapadia's Avatar
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    our body is a good conductor of electricity. so when we touch a charged body charges transfers from the body to us and then to the ground i.e. earth.

    Charges are transferred through conduction convection or radiation.


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  4. #3 Re: Electrical charges, people, and touch-lamps 
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    Quote Originally Posted by rxan
    I have a bunch of questions regarding electrical charges and people:

    1. Does charge require a closed circuit in order to move?
    Yes, but a circuit with only a voltage source and a capacitor cannot carry a steady state direct current, only a transient. So even though the electrons do not actually flow all the way around the circuit, we would call it a closed circuit.

    2. (relates to 1) When you shock someone, I assume this is charge moving from one person to the other. What basic circuit would be at work here? Where is the charge going? To ground?
    The charge is going to the other person (Who is acting as a capacitor plate).

    3. I read that touch lamps generally work because they have a charge, you touch them and some charge moves from the lamp to you, and the lamp registers this. What basic circuit would be at work here (regarding the charges, not the lamp's inner workings)? Where is the charge going? To ground?

    Thanks!
    I believe those work on alternating current. With a-c the charge does not go anywhere, it goes back and forth. And yes, the ground plane would act as a conductor as would the capacitance between you and the lamp.

    Quote Originally Posted by anand-kapadia
    Charges are transferred through conduction convection or radiation.
    No, you are thinking of heat. I don't believe there is any way to radiate a charge. Convection? Well, I guess electrical charges are built up by air convection currents, which results in lightning.
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  5. #4  
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    Quote Originally Posted by anand_kapadia
    our body is a good conductor of electricity. so when we touch a charged body charges transfers from the body to us and then to the ground i.e. earth.

    Charges are transferred through conduction convection or radiation.
    Our body is a good conductor when the current has passed the skin, which has a high resistance.
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  6. #5  
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    Quote Originally Posted by thyristor
    Quote Originally Posted by anand_kapadia
    our body is a good conductor of electricity. so when we touch a charged body charges transfers from the body to us and then to the ground i.e. earth.

    Charges are transferred through conduction convection or radiation.
    Our body is a good conductor when the current has passed the skin, which has a high resistance.
    Oh then if it is so then why do we get a shock when we touch an open wire.
    Also, when we touch a charged electroscope why does the electroscope gets uncharged.
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    Forum Masters Degree thyristor's Avatar
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    Well that's not contradictive with what I said. Obviously the potential is enough great to allow the current to pass the skin.
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  8. #7  
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    Quote Originally Posted by anand_kapadia
    Quote Originally Posted by thyristor
    Quote Originally Posted by anand_kapadia
    our body is a good conductor of electricity. so when we touch a charged body charges transfers from the body to us and then to the ground i.e. earth.

    Charges are transferred through conduction convection or radiation.
    Our body is a good conductor when the current has passed the skin, which has a high resistance.
    Oh then if it is so then why do we get a shock when we touch an open wire.
    Also, when we touch a charged electroscope why does the electroscope gets uncharged.
    It depends on the voltage in the open wire. When my hands are dry, I can touch the hot wire in the house 110 volt circuit and the neutral with another finger on the same hand, and often not even feel it. Because my hands are like welding gloves.

    If I wet my fingers, and I do, to test a circuit before I get comfortable with it. Then I feel it good.

    I can touch a single hot wire, standing in dry boots on dry ground and feel nothing. Even higher voltage, under three hundred volts to ground.

    Standing in dry boots on dry ground, I can touch high voltage, high frequency, shielded by Bakelite. And not feel a thing. I can touch my bare forearms to a large grounded aluminum welding table as well and feel nothing.
    Yet if I step into a puddle of water, I get a very strange, ants crawling all over my body feeling. With an actual ionizing force against parts of my body.
    That can only be caused, by the fact that the water that is a dielectric, disconnected me from a solid conductor, skin, socks, boots, cement.

    Liquids tend to arc, and create or allow high voltage. That is why they are often used in batteries and electrical generating equipment/capacitors.


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    William McCormick
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  9. #8  
    Forum Senior anand_kapadia's Avatar
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    All u said about u didn't feel anything means that the current passes through the body to the ground or that our body doesnot conduct electricity.
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    Forum Masters Degree thyristor's Avatar
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    Our body can conduct electricity. The way the current goes depends on if the person is isolated to the ground potential and if the source is connected to the ground potential.
    If both the person and the source are connected to ground potential the current will go through our body to the ground potential.
    You see the circuit must be completed so one of them can't be connected to something the oner isn't connected to if there's going to be a current.
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  11. #10  
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    It depends on what you consider a good conductor
    http://en.wikipedia.org/wiki/Electric_shock
    In general, dry skin is poor conductor having a resistance of around 10,000 Ω, while skin dampened by tap water or sweat has a resistance of around 1,000 Ω.
    William, you are an accident waiting to happen. It's a wonder you have lasted this long, doing stuff like that.
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    Quote Originally Posted by anand_kapadia
    All u said about u didn't feel anything means that the current passes through the body to the ground or that our body doesnot conduct electricity.
    Dry insulating solids, raise in voltage faster then metals. Because the only way to stop electricity is with electricity. So an insulator on a wire raises in voltage so fast that it repels electrons from leaving the wire, or repels ambient voltage around the outside of the wire, from being absorbed by the wire.

    Nothing can stop electricity, except electricity. Air stops your common, battery from draining a lot, by rasing in voltage, by creating an arc, near the terminal short of electrons, this stops most of the flow. However a flow is present. You can check this with an oscilloscope and a piece of aluminum foil.

    Water does not actually lower ohms. It actually creates an ARC, an ARC can be easily 30,000 volts of often low intensity/amperage current.
    When you are connected through this liquid, you become a plate with an opposite charge compared to what is feeding the other side of the liquid.

    The liquid allows for a more rapid polarization of your body, because the liquid is slower in conducting. Unlike your dry skin just raising in voltage rapidly and countering the current so it does no flow. Your wet skin now raises in voltage enough to carry devastating voltage without creating a diode to stop the flow.

    Your dry skin creates a diode that repels incoming or outgoing electrons. The wet skin just lets it flow. But it is through the ARC that it flows. Just like in a capacitor.

    Gases and most liquids tend to create an arc, when put under electrical pressure or when they are put into an electrical loop. Like in fluorescent bulbs and neon bulbs. In these cases it is obvious what is taking place. With lesser current you may be able to set up some experiments to witness it.

    Light can often be seen in electrolytic battery cells.



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    William McCormick
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    Quote Originally Posted by Harold14370
    It depends on what you consider a good conductor
    http://en.wikipedia.org/wiki/Electric_shock
    In general, dry skin is poor conductor having a resistance of around 10,000 Ω, while skin dampened by tap water or sweat has a resistance of around 1,000 Ω.
    William, you are an accident waiting to happen. It's a wonder you have lasted this long, doing stuff like that.
    All the guys I work with tend to be a bit more crazy then me. I am usually the more safety conscious. I have worked with hundreds of electricians and I am not the most outrageous.
    I know two electricians and the one fellow was working with me welding. He came in one morning and said the other electrician at a party the night before, climbed up the electrical mast, and bit the power cable to the house and hung there by his teeth.

    Now I can assure you I won't be up there doing that. On purpose anyway. Ha-ha.

    But when you do this kind of work, it is dangerous. I work on high voltage outdoor equipment all the time. In the tri state area. In the rain in the snow. Is it safe heck no. But that is the job.

    I much rather test for power, when I am grounded to something by a dry hand, when I am in control of the experiment. Rather then get comfortable up against the equipment and get bit later, when a wet jacket or wet rain gear is up against a lot of metal.

    So I always test the power first with the meter and then with my fingers. Because I have had a digital meter freeze up about ten times in my life.

    Once I was working in a bar, it was a new customer. I was up taking out an egg crate in the drop ceiling. They were using the drop ceiling as a common return air duct, to a package unit on the roof. Wrong way to do it. But they did not have enough for new duct at the time.
    I was up on a ladder, and found a mangle of, BX (metal armor or greenfield) covered wire. On top of the egg crate grill. So I touched all the wires while holding onto the grounded metal drop ceiling supports. And it was all of the same polarity.

    I shook it around some and felt fairly assured that there were no poor connections. I pick up all this spaghetti and go to move it.
    With that a wire that an "electrician" or previous owner had taken off of something, and left uncapped. Also hung it over an I beam eight feet above the drop ceiling, out of plain sight. It looked like it went up to the roof. It fell onto my back and wet "T" shirt. So now I am doing a rather comical dance of joy up on the ladder. I could not really get all the spaghetti off of me. I was loosing my balance on the ladder. And decided to drop the wire, and dive for the floor. Rather then to fall backwards onto the bar.

    I kind of just fell on all fours. And then rolled incase that hot wire wanted some more of me. It dropped out of the ceiling about four feet. And hung rather harmlessly. I guess the wire met its match. Ha-ha.

    But no matter what you do in this business. It is going to be dangerous.

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    William McCormick
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  14. #13  
    Forum Senior anand_kapadia's Avatar
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    No, you are thinking of heat. I don't believe there is any way to radiate a charge. Convection? Well, I guess electrical charges are built up by air convection currents, which results in lightning.



    But negative charges i.e. electrons can be transferred through B-rays. By Radiation.

    Now i agree charges are transferred through conduction, induction and even radiation.


    Also it is agreed that our body conducts electricity at certain small voltage too.
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