what is a circuit and how does it even work how does electricity work
all right so the the one thing that is the most helpful to understand is that electricity needs
to make a loop we have a complete Loop this is a circuit so say we have a Transformer out here
on a pole somewhere that is just a single piece of wire going through it at one end
to have the start of our Loop and then say we have like a light bulb on the other end
it's another loop so from the bottom you know like a little part of the bulb to the screw
shell this is probably going to be connected on one side and this is going to connect on
the other side but essentially what you have on the inside is just a light filament that touches
one side of that bulb and the other side of that bulb so you have a coil of one wire on
the other end you have a coil of one wire and in between them we run two wires one to each
one that's it that's a complete circuit that's a loop that's how current travels if you break
this Loop and and like pull it apart current can't travel through here there's no flow the only way
current can travel and electricity has any kind of electromotive force is if you have a complete Loop
once you connect a switch you complete the loop light bulb turns on once you flip the switch off
switch opens no more current flow so that is how electrical Works essentially but there's a couple
of quantities that we want to think about so when we talk about electrical terms we're always using
volts amps ohms and Watts you might not use Watts you might use like volt amps if you're talking
about like reactive power you're talking about storage like instead of energy being consumed
you're talking about energy being stored you might talk about capacitance like there's some other
capacitive reactants and inductive reactants and things like that you can learn about that stuff
later because that's just kind of like extra details into a circuit that are not necessary
to really understand electrical at a base fundamental level so what we have is volts volts
equals pressure how much pressure are we putting out on the primary side of our circuit from our
source there's a generator spinning somewhere it might be Niagara Falls there's water falling
and it's making something spin because they're utilizing that water to spin something and that's
how you get a certain amount of pressure through the system and if you create more motion or if you
change the Dynamics of the magnetism inside or or any of that there's different ways in which
you can get more or less pressure you can have a smaller thing spinning or a bigger thing spinning
so you're going to get different pressure or a different voltage from whatever is generating
and spinning and making that movement possible so over here we've got a spinning let's just do like
a little thing like this like say we have like a fan spinning fan spinning over here and uh from
that fan spinning we're getting a a pressure that is delivered to our circuit so that's voltage we
might test 12 volts between here we might test 125 volts we might test 480 or 10 150 000 whole
bunch of different voltages but all we're talking about with voltage is how much pressure is there
in the system 12 volt systems with like low voltage lighting on the grass very very low
pressure not very much pressure at all and if you add too many loads on a system you could actually
drop voltage or drop pressure over the entirety of that circuit to the point where at the end of it
nothing will light up anymore because there's not enough pressure to make it through the
amount of resistance that's inside of that thing there's just too much opposition to the pressure
so nothing's going to move it's like a bunch of people in the crowd right like you try to get
everybody to move but at a certain point there's like a saturation where the pressure being applied
by all the people in the back and the resistance from the people on this side like nothing's Moving
And so there's no byproduct of that there's no actual movement or flow to create anything
so that is the way that we think about voltage voltage is often called a difference of potential
because on one side you have what we can think of as like a negative potential and the other
side you're going to have what's considered a positive potential one of them is pushing
while the other one is pulling at equal force and at the exact same time so when we have that
spinning going on that's in a generator back at a power plant there's two wires that come off of
that generator and one of them while this magnet is spinning inside of it is has a pushing motion
but at the same time since it's spinning while that one is pushing the other one's pulling so
you can kind of think of this back and forth that's happening between these two wires and
with alternating current it's alternating it's going back and forth 60 times a second so it
kind of it's like this fast like vibration that's happening much faster than that by the way so it's
almost like a constant we almost experience it as a constant we don't see a light bulb or load
on this side blinking but if we captured the light bulb with a camera and sat and watched and slowed
everything down you would see this light bulb is blinking but because our eyes only you know like
we observe reality at a certain frame rate so to us it actually as fast as our brains and our eyes
can process it looks like it's just a solid thing you can increase frequency and you can make things
blink even faster there's a lot of different again that's just another like angle that we
could look into a basic circuit but that's adding complexity that we don't need to really add right
now but there's a certain amount that a load is essentially blinking because it's shifting
back and forth Push Pull Push Pull voltage is the amount of pressure that we apply what we're
actually pushing with that pressure is called current and we say amperes are for the flow
how much flow of charge is going through this you can kind of think of it like a whole bunch
of little BBS if we added up pressure to one side and this is just like a tube full of BBS
all those BBS are going to start moving well each one of the BBS how many BBS move percent
second it's a rate amperage is the same thing how much flow is happening per second so a lot
of current means that there's a lot of charges moving per second very little current you like one
amp is very few charges moving per second so just remember it's a raid at how much flow it's like
uh in plumbing you might have liters per minute or liters per second it's how much water is actually
flowing through this complete Loop this complete enclosed system so a lot of times people use water
as an analogy to understand what's happening in electrical currents and for the most part
it's a pretty accurate thing some of it is not 100 but you can kind of conceptualize water in
wires sorta so that is flow if we wanted to take an ammeter and say we connected like a 240 volts
to some wires and we had a load that over here that's like a you know again like a light bulb
we could actually take an ammeter and the ammeter is going to or a clamp on ammeter is
going to sense how strong of a magnetic pulse is happening around these conductors because
there's an expanding and collapsing magnetic field remember this is a pulsing system so
it's going to detect how much current is flowing through because the more current the stronger that
that pulsing is going to be it's not going to change like how many times it's blinking it's
still blinking at a solid rate at 60 hertz or it's you know 60 times per second in our situation but
it's going to be pulsing stronger at 60 times a second so it's going to detect that there's much
more current flowing through because it's just quantity of charges or quantity of BBS flowing
through so that is amperage it's it's there's there's copper and copper is made of atoms and
atoms have electrons and when you influence an electrical field around a particle that field
can push that particle and so the moving back and forth in an AC circuit just detects that
movement so that's amps when you're talking about amperage we don't send amps to stuff we
apply pressure we connect at the other end a load and a load has a certain amount of resistance to
it and if we don't have any resistance and we just take like another wire and connect them a whole
crap load of current is going to flow current is always trying to flow at its maximum so electrical
current is always trying to like basically travel the speed of light and it's our responsibility as
electricians to try to slow electricity down so that we can actually utilize it for something
useful so a light bulb the use that we get out of it is that we want light so what we do is we
figure out how much resistance do we need to put inside of this bulb like what do we need
to do to the conductor to make sure it has enough resistance so that when we hook it up to the black
and the light it doesn't explode but instead it just starts to glow red hot or yellow hot
and now we have a wanted effect there's a little bit of heat loss that happens you can kind of
feel that that energy that's being applied is escaping in heat but it's also escaping in life
so the escaping that's happening the reaction from applying a resistance to a pressure or a voltage
is that it gives off something and that something is what we call wattage so wattage is uh power
consumption it's kind of a wanted effect it's it's energy escaping something so a toaster we
love wattage in a toaster right because it gives off heat and we're trying to use that heat to heat
up bread and toast it so we create another kind of little wrapped up coil of wire that we call a
heating element and we hook that heating element through a cord to the black and the white we just
hook it up and we allow current to flow through and it doesn't like it's not explosive because
the amount of resistance that are in those elements is so much and you could add more
elements and make it even crazy but then there wouldn't be as much heat there's just too much
opposition there's too much resistance so those are our last two values we have ohms which is
always our opposition again in the crowd of people you're applying pressure you get a whole bunch of
resistance on one side you're not going to get the whole thing to move you're going to have a
stoppage that happens so there's a certain point where you can have so much resistance in something
that current can't flow through it so if you lessen the amount of resistance more current
can start to flow and if there's no resistance or very very little it's going to flow like crazy so
controlling the resistance everything that we hook in every electrical device every microwave fridge
every vacuum cleaner that we plug in TV router charging your phone everything we're basically
just taking a certain amount of resistance and introducing it into a circuit that has pressure
and we're allowing a certain amount of current to flow and if you maybe like hook up your phone to
the wrong charger maybe the resistance inside of that charging block is not set up for your phone
so you could allow too much current to flow through that thing and you could destroy your
phone so you start to understand like oh it's it's all about resistance every load everything that we
say we're hooking a load up a light bulb would be a load or a motor would be a load we're hooking a
certain amount of resistance to a circuit where impedance to allow current to go through it at
whatever level it is designed to have current go through it light bulbs will blow up if you
hook 240 volts to them if they're only rated for 120 volts somebody sat in an engineer calculated
all right if we put a pressure of 120 volts and we take a resistance of like who knows I don't know
5 ohms or something how much current is going to be drawn through that circuit and through
that bulb and it can handle it or is it going to explode or is it not going to be is it going to
be too much resistance where it's not going to matter the pressure is not going to allow that
current to actually flow because we have too much resistance against it that's it that's
electrical that's the whole of everything you need to understand watts is what happens to the load as
a result of introducing that load to a pressure so we introduced say 100 watt light bulb well we know
that 100 watts of power is going to be consumed or you can kind of think of it as like lost there's a
difference between power consumption and power loss and in loads that are not like resistive
loads that don't just have like a wire in them you could have things called reactants you could
have things called capacitance inductance there's a lot of other values again the deeper you get in
your career where you start wanting to evaluate things on a little bit deeper level to figure out
what's going on that's when you should start looking into things like inductive reactants
capacitive reactants and understanding how they affect things and knowing the difference between
reactive power knowing the difference between like power factor and and what is wattage versus KVA
like volt amps or thousands of volt amps because VA and wattage are very similar they're almost
like a one-to-one thing but there's a different reason when you're talking about energy storage
versus expending energy a toaster is expending energy a lot bulb is expending energy as light in
this heat that sometimes we have storage systems we have capacitors and things like that that we
want to maintain storage of that power and so we look at that as VA or volt amps instead of
thinking about it as wattage so they're slightly different but again you don't need to know any of
that that's just crazy stuff that if you start getting like super nerdy and you just want to
watch more videos and and read books that's stuff to look into when you get to that point but just
understand the entirety of what you do every day is there's a house in between here right and in
that house we're putting these little loads and outside out the street there's a Transformer and
we're just creating a whole Loop through the house every single load that you hook up creates a loop
and when that Loop is created current is able to travel and you have to unplug it or turn a
switch off to get it to stop traveling but each individual load that you plug in has a different
amount of resistance inside of it that is going to allow current to flow differently so some things
that you plug in only like 10 amps are going to flow some things you plug in 60 amps are going to
flow because of the amount of resistance inside of that that they want to allow current to flow
through because they want this thing to have a certain amount of wattage or a reaction that is
useful to us so that's it that's the whole shebang hope that helped share it with your teachers share
it with your classmates share it with your buddy driving down the street well not if he's the one
driving I guess if you're driving neither one of you should be sharing things while you're
driving but I hope this helps some of you all understand conceptually the entire system of how a
circuit works and can help you in your electrical nerdum love you crazy people see in the next one