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    Default Very basic question about electricity

    Hey, this is probably a pretty silly question but I'll ask it anyway, I have heard of the terms static electricity, and I know what it refers to, but what is the other kind of electricity, the type that flows in wires, generally refereed to as? I've heard some people say "current electricity" and yes I realize there is current, and I know ohms law and stuff, but I've used the term current electricity numerous times and confused some of my mates. So I don't know what else you'd call it.

    Gab



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    Bloody good question, wouldn't have a clue myself - perhaps Phased electricity ?? (single sand 3 phase )
    In hindsight I should have posted my Facebook status as: "I've blown the head gasket on my 1997 XR3i" rather than "I've just buggered a 14 year old escort".
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    Take your pick from It depends on application.

    Edit: Had a longer think about your question, so I'll go for the simple answer you may be looking for.
    The electricity that comes into your house that you plug your devices into is AC (Alternating Current), 110Volts or 220Volts depending on where you live.
    In Australia that is commonly known as 240VAC although it is actually 220V & can vary between 200V & 240V unless you have a power spike, a brownout or a blackout, hence the need for surge boards & in some cases UPS devices.
    Some of the appliances you have in your house are 220VAC appliances, however some are not & have an AC to DC converter either internal or external, which converts the power to DC (Direct Current) at a lower voltage.
    So even the simple answer becomes a little complicated.
    Perhaps Alternating Current is the wording your after?
    Last edited by Tiny; 16-07-13 at 11:12 AM.
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    Quote Originally Posted by gab250 View Post
    hey, this is probably a pretty silly question but i'll ask it anyway, i have heard of the terms static electricity, and i know what it refers to, but what is the other kind of electricity, the type that flows in wires, generally refereed to as? I've heard some people say "current electricity" and yes i realize there is current, and i know ohms law and stuff, but i've used the term current electricity numerous times and confused some of my mates. So i don't know what else you'd call it.

    Gab
    EMF

    Last edited by ol' boy; 16-07-13 at 09:48 AM.
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    As an electrician, we were taught to use the term - electricity. No qualifier, just good old electricity.

    If you've been in the Navy, you might use the term 'green-steam'.

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    Generated electricity/power.

    This can be from fossil fuels, hydro, solar, wind etc.

    Regardless of how it's generated, as Onefella said, it's all just referred to as 'electricity'.
    Last edited by mtv; 16-07-13 at 12:59 PM. Reason: added info

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    Whatever you call it, don't touch it, it bites!

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    The History Channel has recently run a program called 'Mysteries in the Museum' and a recent episode dealt with the 'Current War' between Edison and Tesla and his partner, Westinghouse.

    Back then it was referred to as Current, ie DC Current or AC Current but as you say its now just called 'Electricity'.
    I stand unequivicably behind everything I say , I just dont ever remember saying it !!

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    Wink The correct nomenclature adjective is " Reticulated ".


    Reticulated Electricity supply. Also should specify whether HV, LV and AC or DC.

    Reticulation is defined as supplying via a network.



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    Static Electricity is a motionless charge built up on the surface of non conductive object, so that's why it's called static electricity. Electricity that flows through a conductor (AC or DC) is energy in motion, so i'd say it's, as previously stated, EMF (electro motive force) or electrical energy. But the technical term i prefer to use is: bitey bitey stuff that lives in wires.

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    Thats about it Bob..... Keep the Smoke inside the Wire!!!
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    My very basic answer:

    Electricity is the potential to move free electrons. Everything else is a consequence of that.
    Update: A deletion of features that work well and ain't broke but are deemed outdated in order to add things that are up to date and broken.
    Compatibility: A word soon to be deleted from our dictionaries as it is outdated.
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    Bob has pretty much nailed it.
    Static electricity tents to be more about how the electricity is generated, by a stray static (stationary) charge.
    There are many generators which harness static charges and create useful electric charge (or power) from them.

    The most classic example every high school student sees is a Van De Graff generator. It looks like a complex machine from a science fiction movie but inside it
    is nothing more complex than a belt. Static charges don't move on their own, but when they are deliberately moved, they can induce charge on other objects.
    So if you stroke a perspex rod with a nylon cloth, the stray charges in the cloth induce the opposite charge in the rod.
    When stroked again and again, these charges build up more and more.

    This principle is the same in the van de graff generator. A stray charge on the belt (lets say it's a tiny negative charge) is on the side of the belt moving down.
    As it moves down, it passes the belt on the way up and induces tiny positive charges which move up.
    As the positive charges move up, they induce more negative charges moving down, which in turn generate even more charges moving up.
    At the bottom of the belt is a conductive brush which removes the negative charge to earth. At the top, another brush collects the charge and stores it on the dome.
    The shape of the dome and the position of the end of the belt in it is critical.

    The charge on the dome is just like any other electrical charge. It can flow and discharge given a conductive path.
    A static charge like that on the belt cannot move on its own.

    Another favourite generator is a Whimshurst Machine. It works on the same principle. The difference is that it is two insulated plates which had metal blades on each.
    The two plates rotate in opposite directions. A stray charge on one of the metal plates induces charge in other plates moving in the opposite direction. Brushes collect the charge from
    each plate as they spin around.

    But my all time favourite static generator which you can make at home is called a Kelvin Generator.
    It consists of four tin cans and two wires and two sources of flowing laminar water, like that from a tap or tube.
    The two flows of water fall through a tin can each without making contact with it and then that water is caught in another can underneath the first.
    Holes in the bottom of these tins allow it to drain. The water can then be pumped back to the tap at the top if the water is recycled.
    This one doesn't recycle the water, but powers a fluro tube.

    It's important to realise that water is an insulator. As it falls through the first tube, a stray charge from the tube is induced on the water which is then collected in the tin below.
    That charge is then taken by the wire to the tube on the other side to induce an opposite charge on the water. Which in turn is collected and used to induce and even bigger charge in the first side.
    If the fluro tube is replaced with a large capacitor a simple device like this can generate and store a dangerous amount of charge. But without the capacitor, kindergarden children can build it and make it work safely.

    ---

    Apply these thoughts of a moving static charge to thunderstorms. Lightning only occurs in one type of cloud. A cumulonimbus. Inside the cloud warm air is rushing up a high speed.
    It takes water vapour up with it which condenses as water or freezes as hail. As these objects pick up more mass, they start to fall. As they do so, they pick up a static charge from dust particles moving up in the air mass.
    As the water drops fall they start to evaporate or hail sublimes. As its volume decreases, it's surface charge increases. Their mass also decreases to the point where they are now light enough to be picked up by the
    fast rising air mass. So what ends up happening is the larger heavy objects are falling and lighter objects rising. As they pass each other they induce greater and greater charge upon each other until a point is reached where
    the tension in the air snaps and a bolt of lightning is created as areas of the atmosphere discharge.
    Last edited by trash; 23-07-13 at 03:02 PM.
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    Thanks trash, you sound like a skool teecha (sic.)

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    It's important to realise that water is an insulator.



    I have a tiny problem with that sentence in Trash's informative reply.

    One day when I was about 15, I had a fit of the 'Stupidities' and decided to see if I could make 'sparks' across the pins of an old electric jug.
    This jug typically had no top so while it was happily trying to heat the water inside, I sprinkled a few drops across the pins to see what happens and nothing did.
    So I 'Upped' the Stupidity level an other notch and sprinkled some salt into the water between the pins gradually until it began to throw some rather yellowish sparks.
    At this point, either the gene for 'Self Preservation' kicked in (unlikely) or the fear of getting a kick in the arse from my employer because I was at work making the 'Morning Tea', I turned the jug off, dried the water and turned it back on until it boiled and made the 'Morning Tea' with nobody the wiser into my Foray with the Conduction of Electricity.
    Today I have been wondering about that 'experiment' and based on the fact that electricity, like water' always takes the easiest path, if the element hadnt been in circuit, could I have had a 'quicker' display of sparks either from just the plain water alone or with less salt in it ?

    Does the conduction of electricity in water depend solely on the 'impurities' in it or will even the 'cleanest' water allow passage?
    I stand unequivicably behind everything I say , I just dont ever remember saying it !!

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    Default Methinks you should use ice in your Scotch, not pure water !

    Conductivity is a measure of how well a solution
    conducts electricity. To carry a current a solution must
    contain charged particles, or ions. Most conductivity
    measurements are made in aqueous solutions, and
    the ions responsible for the conductivity come from
    electrolytes dissolved in the water. Salts (like sodium
    chloride and magnesium sulfate), acids (like
    hydrochloric acid and acetic acid), and bases (like
    sodium hydroxide and ammonia) are all electrolytes.
    Although water itself is not an electrolyte, it does have
    a very small conductivity, implying that at least some
    ions are present. The ions are hydrogen and hydroxide,
    and they originate from the dissociation of molecular
    water. See Figure 1.
    Conductivity is not specific. It measures the total
    concentration of ions in solution. It cannot distinguish
    one electrolyte or ion from another.
    Not all aqueous solutions have conductivity. Solutions
    of non-electrolytes, for example sugar or alcohol, have
    no conductivity because neither sugar nor alcohol
    contains ions nor do they produce ions when
    dissolved in water.
    APPLICATIONS OF CONDUCTIVITY
    Conductivity measurements are widely used in industry.
    Some important applications are described below.
    • Water treatment. Raw water as it comes from a lake,
    river, or the tap is rarely suitable for industrial use. The
    water contains contaminants, largely ionic, that if not
    removed will cause scaling and corrosion in plant
    equipment, particularly in heat exchangers, cooling
    towers, and boilers. There are many ways to treat
    water, and different treatments have different goals.
    Often the goal is demineralization, which is the
    removal of all or nearly all of the contaminants. In
    other cases the goal is to remove only certain contaminants,
    for example hardness ions (calcium and
    magnesium). Because conductivity is a measure of
    the total concentration of ions, it is ideal for monitoring
    demineralizer performance. It is rarely suitable for
    measuring how well specific ionic contaminants are
    being removed.
    Conductivity is also used to monitor the build up of
    dissolved ionic solids in evaporative cooling water
    systems and in boilers. When the conductivity gets
    too high, indicating a potentially harmful accumulation
    of solids, a quantity of water is drained out of the
    system and replaced with water having lower conductivity.
    • Leak detection. Water used for cooling in heat
    exchangers and surface condensers usually contains
    large amounts of dissolved ionic solids. Leakage of
    the cooling water into the process liquid can result in
    potentially harmful contamination. Measuring conductivity
    in the outlet of a heat exchanger or in the condenser
    hotwell is an easy way of detecting leaks.
    • Clean in place. In the pharmaceutical and food and
    beverage industries, piping and vessels are periodically
    cleaned and sanitized in a procedure called cleanin-
    place (CIP). Conductivity is used to monitor both the
    concentration of the CIP solution, typically sodium
    hydroxide, and the completeness of the rinse.
    • Interface detection. If two liquids have appreciably
    different conductivity, a conductivity sensor can detect
    the interface between them. Interface detection is
    important in a variety of industries including chemical
    processing and food and beverage manufacturing.
    • Desalination. Drinking water desalination plants,
    both thermal (evaporative) and membrane (reverse
    osmosis), make extensive use of conductivity to monitor
    how completely dissolved ionic solids are being
    removed from the brackish raw water.
    THEORY AND APPLICATION OF
    CONDUCTIVITY
    Theory
    Application Data Sheet
    ADS 43-018/rev.D
    January 2010
    FIGURE 1. Salts, acids, and bases are electrolytes.
    They dissolve in water to form ions.
    Although water is not an electrolyte, a very small
    concentration of hydrogen and hydroxide ions are
    always present in pure water.
    NaCl Na+ + Cl
    - salt
    acid HCl H+ + Cl
    -
    base NaOH Na+ + OH
    -
    water H2O H+ + O




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    Yes, pure water is an insulator.

    Water with certain impurities becomes a conductor.

    Yes, if your jug had power to the 'pins' but no element in line, there would have been more current flow through your tap water, and you would have got a 'result' almost instantly. The heating element was a very low-ohm resistor and you had to make the water very low-ohm as well, to get enough current to cause a flash-over.

    I've seen some crazy dangerous 'cup-heaters' just made from two spoons held a few millimeters apart with tape, and a mains active and neutral, connected to each spoon respectively. The 'heater' is dropped into a cup of water before the unit is plugged in. Then the thing makes a terrible noise arcing-out in the water, and it gets hot. Simple, yet deadly.

    edit: gee beer4life, you sure can type fast!
    Last edited by Onefella; 24-07-13 at 02:49 PM. Reason: methinks though dost cut & paste much.

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    Actually, water (pure) is a conductor.
    I'm of course fudging the term a little here.
    Disassociation of water molecules will always allow some tiny current to flow.

    But to answer gordon's question. The more impurities, the better it will conduct.
    Last edited by trash; 24-07-13 at 11:20 PM.
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    Quote Originally Posted by trash View Post
    Actually, water (pure) is a conductor.
    ok, out of my league here. But my statement came about from my experience maintaining very large water-cooled thermionic vacuum-tubes. The water for the cooling had to be extensively purified so as to be an (almost?) pure insulator. If the water wasn't changed regularly, it would get enough impurities from the rest of the cooling system to cause arcing and flash-over in the HV sections. A very bad thing for a 500kW valve.

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    I think we can all agree at some point water can be both an Insulator and a conductor and based on Onefella's experience, keeping that balance takes care.
    Would I be wrong in suggesting that even the purest water given a high enough 'Charge' , be it Current, Voltage, Frequency as in AC, eventually reach that point and go from Insulator to conductor?
    'Pure' water doesnt exist in Nature so for those like me it would be safer to believe that water can conduct and treat it accordingly.
    I stand unequivicably behind everything I say , I just dont ever remember saying it !!

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