Volts, Amps, and Watts Explained
Techquickie
·Techquickie
·2017-05-06
·
1,276 words · ~6 min read
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so when you get your home energy bill it
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lists the usage in kilowatt hours but
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when you go to the store you'll see things like 12 watt light bulbs 9 volt
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batteries and vacuum cleaners with 15
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amps of sucking power but what do these numbers even mean i
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mean why do we have so many different units
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to measure something that seems as straightforward as electricity
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surprisingly the answer isn't just so appliance companies and physics
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professors can confuse you it's because several important things have to happen
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in an electrical circuit for electricity to flow and for work to be done
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you can think of a circuit kind of like the faucet on your kitchen sink if you
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want water to come out you need two things you need the water itself and
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some pressure to force it through the pipes outer faucet and into your neti
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pot similarly an electrical circuit uses
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electrons to carry the electricity kind of like the water in our faucet analogy
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but those electrons need something to push them along a circuit this
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electrical pressure is what we call voltage and is often provided by two
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terminals one with a positive charge and
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one with a negative charge so on a
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battery electrons flow from the negative
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end through whatever it is you're trying to power and then into the positive end
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where they'll stay unless your battery is rechargeable if you're plugging
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something into the wall this voltage is instead provided by your power company
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and although voltage just measures how
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strongly electricity is being pushed through a circuit it's important because
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many circuits are designed only to accept a certain number of volts
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which is why the hair dryer you bought in monaco might release magic blue smoke
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if you plug it in in new york so now that you know what volts are what
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about amps well in this context amp isn't short for
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amplifier but rather for ampere which is a unit of
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how much electrical charge is flowing past a given point in one second so when
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you put volts and amps together you can
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tell how much current is flowing and how
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hard it's flowing multiply these numbers and you get
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finally our third unit the watt
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let's go back to our water analogy for a second let's suppose you wanted to spin
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a small water wheel because you just like
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watching things spin or i don't know maybe you have it hooked up to a generator
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let's say you have a really powerful water pistol that forces water through a
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tiny nozzle even though the small nozzle means the
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total volume of water flowing per second
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isn't all that much you wouldn't want to feel your swimming pool with it the high
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pressure creates a strong jet that can
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spin the wheel easily but suppose instead of a water gun you have a much
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wider hose that doesn't push the water out nearly as strongly but because the
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hose is a lot wider more water flows per
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second overall and the wheel ends up spinning at the same speed it did with
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your water gun if we think of the hose
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and the water gun pushing out electricity instead of water we could
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say that they're delivering the same number of watts
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for a more practical example let's say you have an 1100 watt power supply for
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your computer that's drawing full load because you're rocking four-way sli or
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something so if you plug that into a standard 110 volt north american outlet
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some simple math tells you that 10 amps of current is running through your power
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supply but if you take that same power supply and use it with a 220 volt
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european outlet you're only drawing 5 amps but since the amount of power in
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watts is the same your computer will work just fine in both places even
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though you're using different volts and amps well that makes sense Linus but why
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the heck then is my energy bill in kilowatt hours is that a unit of time no
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actually scientists are just mean it's a unit of energy watts and kilowatts
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express how much energy is consumed per chunk of time something scientists call
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power which is not the same as energy but if you multiply a kilowatt by an
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hour the units cancel and you're left with a number that shows how much energy
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that you hogged by running your air conditioner gaming rig and novelty lava
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lamp all at once but what if you're more concerned about
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battery capacity instead of what's
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coming out of your walls well if you're buying a replacement battery or a
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battery pack you might see their capacity listed in milliamp hours again
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not time doing the math shows that this is a unit of charge not energy or power
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so going back to our water example this
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is like how much water you have in a bucket not how much is flowing or how
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fast is flowing so a bigger bucket means you could charge your phone more times
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and you can learn more about that and battery banks in this video here
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so go forth then with your newfound knowledge and expertly buy the right
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voltage adapter install the correct power supply or just ace your electrical
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engineering exam if you want to do more with your life than work for some
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thanks for watching guys like dislike check out our other channels comment
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with video suggestions and don't forget to subscribe
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