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electricity in homes

Discussion in 'Electronic Basics' started by conrad, May 6, 2007.

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  1. conrad

    conrad Guest

    How does unplugging electrical applicances(loads)
    save on electricity in homes? I know a load utilizes current
    and consequently produces power. What I don't
    follow is that the way current is provided
    is not like a battery, so you don't have the
    potential for pushing a charge across
    a conductor like you would with a battery
    (that provides an electron on the anode to
    carry back to the cathode). The way I picture
    it is, is that you have wiring that current is flowing
    through and that connects to a recptacle.
    You can control whether current goes to a receptacle
    by using a circuit breaker. But even then, you have
    just inhibited the flow of current from the receptacle
    to the circuit breaker. Up to that point, you still receive
    current(as far as how I picture it). Point being that your
    current flows from a nearby pole for example to your
    home. In which case, you don't have a varying amount of
    current being distributed to your home but the way you
    use that current to power appliances can vary. But nonetheless
    the overall amount is distributed from a nearby powerstation.
    And that amount from the powerstation cannot vary. So anything
    you don't utilize would be lost. What I am getting at is this,
    it would then follow that whether or not you unplug appliances
    in hopes of saving on electricity, the overall amount of electricity
    that is sent to your home cannot be controlled by you, and
    therefore you are not really saving anything on electricity.

    Is my view apt or no?
  2. JeffM

    JeffM Guest

  3. Bob

    Bob Guest


    You pay for the amount of energy used.

    energy = voltage * current * time

    So if voltage or current of time is zero then the energy used is zero.

    Another way of looking at this is:
    energy/time (energy per unit time) = voltage * current = power
    Power is the rate of flow of energy (per unit time).

    Remember, you pay for the amount of energy used. It's as simple as that.

    The voltage is always there at the outlets (120V is the USA). The amount of
    current that flows depends on what is plugged in and whether it's turned on
    or not, so an appliance that's plugged in but not turned on will draw very
    little (if any) current -- thus the energy used (over a given amount of
    time) is very little (if not zero).

    Some commonly-used units:
    energy is expressed as joules or watt-seconds or kilowatt-hours
    power is expressed as joules per second or watts or kilowatts
    voltage is expreseed as volts
    current is expressed as amps

  4. Circa 6 May 2007 13:21:45 -0700 recorded as
    <> looks like conrad
    So then it follows that if you remove the load, you stop utilising current,
    and thus are using no power. Are you with me?
    Let's tackle that misconception first. You most certainly do have the
    potential for "pushing a charge across a conductor" when you use the AC
    provided to your home. How else would any of your electrical devices work?
    You absolutely do have a varying amount of current being distributed to
    your home. The way you use that current determines how much you use.
    Completely wrong. It's correct to say that the amount from the
    powerstation *must* vary in accordance with the demands of the load. If it
    doesn't, imbalances begin to wreak havoc on the grid.

    So, you must change your conclusion that you cannot control the amount of
    power you use in your home. Few things in life are so completely under
    your control.
  5. I think you're missing the underlying point.

    The talk now is of unplugging unused devices because a lot of things
    nowadays draw some current even when turned off, and those miniscule
    amounts of current add up when multiplied by so many devices.

    So that battery charger draws a bit of current even when no batteries
    are in the charger. That ac adaptor that you run your mp3 player at
    home draws a tiny amoung of current even when you aren't using the mp3
    player with it. That tv set, vcr, dvd player, cd player, stereo and
    whatever else that can be turned on remotely draws a tiny bit of
    current so long as it's plugged in, because it needs a tiny bit
    of current to run the circuitry that will take the signal from
    the remote and turn on the rest of the unit. Some devices use
    a tiny bit of current all the time in order to keep settings. So
    if you unplug it each time, you'll have to readjust things each
    time you plug it back in.

    This isn't that far from the old tube sets that were "instant on".
    They could turn on fairly fast because the tube filaments were powered
    up all the time, though usually at a reduced voltage, so they didn't
    take nearly as long to warm up and give you operation.

    But, these things are now pretty common place. I've even seen equipment
    that is not remotely controlled, yet the power switch is on the secondary
    of the power transformer, so it too draws a miniscule amount of current
    whenever it's plugged in. (The reasoning in those cases is likely because
    it's easier for the designer to have the switch control the secondary

    This has nothing to do with some complicated attempt at understanding
    it. Connect something to the AC line, and it will draw some current.
    Do it enough times, and we have enough junk nowadays that it is pretty
    common, and it can add up.

  6. default

    default Guest

    Unplugging equipment has no discernable effect on power usage if the
    equipment's power switch does shut down primary power. A lot of
    consumer stuff uses small amounts of power because the power switch
    only switches off the display, lights, motors while the electronics
    may still be running, or power supply still using current.

    If it gets warm when it is off - unplugging or adding a switch may be
    worth doing. Each individual item's consumption is negligible, all
    together, over time it can be significant.

    Some items are better than others - a clamp on ammeter and way to get
    to one supply wire will tell you which ones waste the most power or
    get one of the plug-in electronic watt hour meters - they can be
    calibrated to tell you what an item is costing you to leave it plugged

    A switch on your hot water heater may easily make a bigger difference
    than all the little gizmos combined. I found the long piping run from
    the water heater to the kitchen sink was costing me big time (even
    insulation doesn't help that much when the pipe itself is cold). I
    switched to using a large SS pot to wash dishes in and heat the water
    on the stove - If it gets cold while I'm using it I can reheat it just

    Modern conveniences like clothes dryers and dishwashers really suck
    down a lot of power or heat energy.

    Range/stove insulation can often be improved by taking off the back
    and checking the condition or looking for hot spots while the oven is
    on - some un-face fiberglass saves money there - and double in summer.
    Oven will maintain temperature better too.
  7. Guest

    We live off the grid with solar panels charging batteries followed by
    an inverter. You really learn what wastes power.
  8. default

    default Guest

    I live on the grid. I admire those that manage their own power.
  9. sparky

    sparky Guest

    An express view satellite receiver uses 14 watts when operating. It
    uses 13.5 watts when it is turned off.

    Many electronic items today only have a switch that makes the consumer
    think they have turned it off. Simply good PR.
  10. Guest

    In Winter, this is not of much concern to me.
    The convenience is additive to the tiny house heating.
    The reduction in thermal shock to electronic circuits is also an
    advantage. In Summer, I tend to turn them off completely.
    I have rearranged each room with an earth leakage safety cutout and a
    single switch (easily accessible) to cut all power to that room. I
    have a very old house with only one outlet per room, and most power is
    drawn through power boards. The kitchen has had a few more outlets

    I have fluoro lights everywhere that is not switched on and off

    I have three 5 Watt CFLs on 24/7/365.
    Here, a Watt for a year costs about a dollar.

    When I go on hols, I have designed and almost built a solar/LED/radio
    setup so that I can turn the mains off completely. Not for economy
    specifically, but for security against fire caused by faulty wiring in
    the roof. jack
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