TechStuff Classic: The Basic Components of Electronics

It's time for Electronics 101. What are the basic components of electronic circuits and what do they do? Jonathan explains.

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Episode Transcript

Speaker 1 (00:04):
Welcome to tex Stuff, a production from I Heart Radio.
Hey there, and welcome to tech Stuff. I'm your host
job and Strickland. I'mond executive producer with I Heart Radio
and how the tech area. It is time for a
classic episode of tech Stuff. This episode originally published on

(00:26):
June two thousand fifteen. It is titled The Basic Components
of Electronics. I bet you'll never guess what it's about.
Don't be alarmed. I'm going in medias race. This is
the middle of the email here or really the end. Lastly,
I was hoping in the future to see topics covered

(00:47):
like how electronics work, transistors, capascitors, chips, etcetera. I worked
at Radio Shack for five years and got really interested
in electronic components, but found them pretty confusing. That is
perfectly understandable. I still have to look up the various
components and remind myself what each one does, because I
don't tend to work with electronic circuits that frequently, and

(01:10):
I know in general what needs to happen, but sometimes
I forget the specifics because there's a lot of stuff there,
and if you aren't familiar, if you're not always working
in that world, it can very easily slip away from you.
And we are talking about lots of different components that
you measure using different units, And after a while you

(01:30):
just start to you know, if you again, if you're
not just naturally inclined to this kind of stuff, you
start to pull your hair out. Except in my case
that's already been done for me, so I just kind
of rubbed my head. So let's start with the basics.
And I know this is going to sound incredibly basic,
but we have to build a foundation before we can
start talking about the components. So electronics are all about

(01:52):
leveraging electricity. Not a big surprise, you're you're leveraging electricity
in order to do something to accomplis something like a
radio is meant to receive and amplify radio signals and
and convert them into acoustic signals so that you can
actually hear them. That that's a simple example. A flashlight

(02:13):
is meant to channel electricity to end up powering a
light bulb, which is essentially a resistor. We will talk
about those that heats up. We're talking about a basic
incandescent light bulb here um and gives off light as
a result. That's your basic use of that kind of electronics.

(02:33):
So we're gonna talk about how electronics control electricity. These
basic components are all used to do that so that
you can accomplish whatever the goal of your electronic device is. Now,
most electronic devices have lots and lots of different components
to them, sometimes worked in various configurations, whether they're in

(02:55):
series or in parallel. I'm not going to get into
all of that because that's be on what I really
wanted to focus on in this episode. Instead, in this episode,
I want to talk about the very basic components and
what they are intended to do. These are the things
that make up the circuits that you would see in

(03:15):
physical circuitry. So if you ever have, uh, you know,
an old electronic device and you were to take it
apart and you saw all these little weird do dads
on a circuit board, I'm gonna tell you what those
do dads do. Dad. Alright, So first we describe an
electronics materials is having electrons that fall into certain energy

(03:37):
bands or electronic bands. Now, the two important ones that
to talk about are the valence band and the conduction band.
Electrons and the conduction band are able to move freely
through the material in question. Assuming the conduction band isn't
totally full, you can think of it kind of like
a think of it like a nightclub. It's a nightclub
that's maybe you know, full, so you can still move

(04:02):
through it freely. Now that nightclubs packed, you're not going anywhere,
so there has to be you know, almost but not
quite full for you to be able to move around.
That's the conduction band. That's the basics of electrical conductivity. UH.
Whereas the valance band is kind of this um this
this basic energy level, and there is a gap between

(04:22):
the valence band and the conduction band. UH. It is
called the band gap. And depending upon the material, that
band gap will be of a certain size, and in
some cases the gap is insurmountable. You cannot get electrons
from the valence band into the conductance band, and you
cannot get them to flow, at least not under normal

(04:43):
operating circumstances. So in that sense, think of you've got
a like a holding room before you can get into
the nightclub, and the the doorway going into the nightclub
has got a big old bouncer, and that big old
bouncers not letting anyone through that's your band gap. You
cannot there's no one even collectively, all of you working together,

(05:06):
you're not gonna be able to budge that bouncer. That
would be as if you were in a non conducting
material and I'll get into more of that later. Whereas
if you're in a room where there's a wide open
door and you're allowed to go through as long as
someone else is coming in, that would mean that you
could flow through properly. You've got you got electrical electrical

(05:28):
conductivity going on there, and I'll talk more about that
in a second. I realized this analogy isn't perfect, but
I'm just trying to simplify things for those who haven't
really taken this kind of class in physics. So a
large gap would represent a great deal of energy needed
to move electrons from the valence band to the conductance band,

(05:50):
and sometimes that gap is so large as to be
impossible to cross again under normal operating conditions. So let's
look at the basic materials that we talk about in electronics, conductors, insulators,
and semiconductors. Pretty simple to understand. Conductors have high electrical conductivity.

(06:14):
That means they facilitate the flow of electrons uh. They
have a nearly full but not completely full conduction band.
Electrons can move freely through this material in response to
an electric field applied to that material. So you apply
an electrical field to this material, it will then allow
electrons to flow through freely. This is the stuff that

(06:35):
moves electrons from point A to point B. You apply
a voltage across it, you get electrons to flow. That's current,
Although technically current flows from positive to negative as opposed
to the flow of electrons, which is from negative to positive.
We can thank lots of early thinkers for that confusion.

(06:55):
So current flow and electron flow are in opposite directions,
Thank you, Benjamin Franklin. Uh. Alright, So then you've got insulators.
These do not have electrons within the conduction band, or
they have a full conduction band, so again no room
for electrons to move around, so there are no free electrons.
They impede the flow of electrons through that material, and

(07:17):
most solids fall into this category. Metals are uh an exception,
but most solids are insulators. So at normal operating parameters,
you wouldn't be able to apply a strong enough electric
field to make them conduct electricity. So you could apply
an electric field to these things, but it wouldn't be
able to jump that gap between the valence band and

(07:40):
the conductance band, so it would just stop. You wouldn't
have any electrical flow through that at all. So we
use insulators for things like insulation on wires where we
wrapped the wires in that to help prevent leakage or interference, because,
as we've talked about many times on this show, the
flow of electricity is also very closely related to magnetism

(08:05):
and vice versa. So you have to be able to
limit interference between different wires if you don't want there
to be that interaction obviously, otherwise you can end up
causing shorts, which is when you have an unintended connection
between two different elements of a circuit and it allows
electricity to pass from one to the other, almost like

(08:27):
you think of it like a short cut, you know,
when we say an electrical short and it means that
the device itself will not work properly because the electricity
is not flowing through the pathway you had intended it
to go in. All right, then we've got semiconductors, and
we'll talk more about them a little bit later, but
in general, semi conductors have an almost empty conduction band

(08:48):
and an almost full valence band, and the band gap
is relatively narrow, so if you don't apply a strong
enough electric field, it acts as an insulator. But when
you apply the right amount of energy and electric field,
it will allow electrons jump from the valence band to
the conductor band and move freely within the material. You
do this by doping the material, which is when you

(09:12):
insert impurities into the semiconductor on purpose. Doping a semiconductor,
which is all about introducing impurities specifically at at predetermined levels,
will determine the energy levels required to do this, and
that's the basis for solid state electronics. We'll get into
more about semiconductors towards the end of this. And we

(09:35):
also have to remember voltage and current, something that I
always have trouble remembering. So voltage is a lot like
water pressure, all right. That's that's the the amount of
electrical pressure being applied, and the higher the voltage, the
more electrons want to move from the concentration of electrons

(09:57):
to the more positive side. Now, the actual flow of
electricity is the current, so they are related but not
the same thing. So voltage and current, and then you
multiply those two de patent together and you get the power.
So voltage times current equals power. Alright, So those are
your basics. Now we're gonna go through and talk about

(10:18):
the very individual components and what they do. So first
we have resistors. Resistor does pretty much what it sounds like.
It does. It resists but does not halt the flow
of electricity. I'm gonna talk a lot about electricity in
terms of water because it is a useful analogy, and
it's also very common to talk about the similarities between

(10:42):
electricity flowing and water flowing when you're discussing these components.
So let's say that you have two different pipes. You've
got a brand spanking new pipe. It's shiny and beautiful
and free from any any irregularities, and it allows water
to flow through the minimum of resistance. That water is
just flowing right through easily. You've got a second, old,

(11:05):
gnarly pipe, and this one's got calcium build up in it.
They're all these bumps and stuff on the inside. So
water actually encounters resistance friction if you will, as it's
flowing through, and it does not flow through as easily.
Resistors are like that old gnarly pipe, and they are
invented on purpose for specific reasons. So why would you

(11:30):
want to have an electronic component that actually slows down
or impedes the flow of electricity for some reason. Well,
sometimes you have to limit the amount of electricity that
can flow through part of a circuit within a given
amount of time, sort of like how a faucet going
back to water, how fauce it can limit how much
water it can flow through your water pipes into your sink.

(11:53):
So you wouldn't want just an on off switch for
the water coming into your home. That water is at
a much higher pressure, know it's it's a higher pressure
to deliver the water to your house. And if all
you had wasn't on off switch and you flipped it,
you would have water blasting through the pipe according to
the amount of pressure that was built up behind it.

(12:13):
That'd be a little bit nerving, especially if you just
wanted to have a nice, frusty glass water. So you
want to have some sort of limiter on that to
control the amount of water that's or the pressure of
the water that's coming in. So resistors reduced the amount
of voltage placed on other electronic components within a circuit
by restricting the amount of current that can flow through

(12:35):
the resistor. The reason why this is important is that
we cannot create a battery for every single type of
electronic device that's out there. It's not practical. So batteries
different batteries. Different types of batteries have different voltages. So

(12:55):
you could, in theory, develop a battery specifically for a
particular type of electronic device that would not require resistors
because the battery is providing exactly the voltage needed for
whatever electronic components are in net. But it's not practical
to do that for everything. We want standardized batteries, and

(13:17):
then we use things like resistors to help control the
voltage in those electronic components so that the right amount
of voltage is applied to those specific parts of the
electronic circuit, rather than having to have a billion different
types of batteries. That would not be practical. So there
are many different types of resistors designed to work on

(13:39):
specific amounts of electrical power. Now, some have changeable resistor
values dependent upon the amount of voltage placed across them.
They're called nonlinear or voltage dependent resistors. Resistor values can
also change when the temperature of the resistor changes UH.
Different types of resistors do this. Some can also be

(14:00):
mechanically adjusted. So it all depends upon what you need
the resistor form. Why what you needed to do, that's
what would determine which type of resistor you would use.
The unit of measurement for a resistor is the ohm
oh h M. Resistor values are ten percent apart from
each other, and resistors are color coded with bands of

(14:22):
color or or rings of color. So the first ring
represents the first digit of the resistors value. So what
you would do is you would look at the first ring,
whatever color it was, you would cross reference that with
the with a color UH index, and we'll tell you
what the value of the resistor is for the first digit.
The second ring tells you the value of the second digit.

(14:45):
So then you've got the two the two digits that
are involved. The third tells you the power of ten
to multiply by, so it might be ten thousand, and
then you would multiply. Let's say that your first two
digits are a twenty two and seven, and you would
multiply that by ten thousand. You have twenty seven thousand homes.
There and the fourth ring would tell you the tolerance

(15:07):
of the resistor plus or minus whatever percentage. Uh. So
the physical size the resistor and the amount of power
it can handle tends to be proportional. So in other words,
the larger the resistor, the more power it can handle.
In general, So those are resistors covers that basic component.
Now let's move on to capacitors. Alright, So capacitors are

(15:30):
similar to batteries and that it's a means of storing
electrical energy, but unlike batteries, instead of creating an a uh,
electrical flow through a chemical reaction that is steady the
entire time, it is designed to release a it's it's
entire stored electrical charge all at once. So let's say

(15:55):
they've got two leads of a capacitor. You have a
difference in voltage across us these two leads. That's when
a capacitor is charged, So one lead has a greater
build up of electrons than the other lead does. Uh. Now,
if you were to connect the leads together, you would
short them. You would have a discharge of that capacitor,

(16:16):
and the voltage would equalize across the two, so you
get a release of a quick burst of electricity, so
capacitors can pass alternating current freely. A C current will
just pass through a capacitor as if it were not
really there. Direct current, however, will charge a capacitor. It
will have that build up of electrons on one side

(16:37):
while the other side doesn't get that build up of electrons,
and then you have that difference in voltage. Alternating current
just will pass back and forth through it without any problems.
So capacitors contain the same fundamental parts. You have at
least two conductive plates separated by a non conductive material
that's the dielectric. The amount of charge held a capacitor

(17:00):
is measured in units called faret's. But a faret is
a large amount of capacitance, so large that you don't
really talk about a ferret. Instead we end up talking
about micro ferrets, which are about a well, which are
one million of a ferret, so much smaller. Ferret, by
the way, not ferret, two different things. Nice Marmot capacitance

(17:26):
is dependent upon surface area, so it's directly proportional to
the surface area of those leads, those those capacity plates.
Um it is indirectly proportional to the distance between the
plates so the greater the distance between the plates, the
lower the capacitance. Uh. It's also uh dependent upon the

(17:46):
dielectric constant of the insulating material. And they are used
for things that need a quick release of electricity rather
than a steady flow. So for example, a traditional flash
on a camera. So you've got an old camera and
you've got the the the flash, Uh, you know it
bursts in this quick burst of light. Will It needs

(18:07):
that quick It needs access to a quick burst of
electricity in order to do that, and that's what capacitors
are good for. And it takes some time for the
capacitors to build up the charge again so it can
do it another time. That's sort of you know, if
you're using the old ones, you hear that noise. It's
the the discharge and then charging of the capacitors that

(18:29):
require you to take a moment between taking pictures with
those old style camera flashes. Now, obviously newer ones use
different a different approach, but you often have capacitors that
actually provide the electricity for those Now, the voltage of
a capacitor cannot change instantly, it's important to remember, and

(18:51):
quick voltage changes in a capacitor produced large current changes.
Capacitor store energy in an electric field. The reason I
mentioned all that is because we're now going to talk
about inductors, and inductors are kind of, um, the opposite
of capacitors, or really maybe not even opposite is the

(19:13):
right way of saying it. In many ways that they
behave in opposite ways than capacitors do. But we'll get
to that. We'll be back with more of this classic
episode of tech stuff after this quick break. So basically,

(19:36):
an inductor at its most basic level is a coil
of wires, so sometimes we just call them coils and
not inductors. Uh. They deal with what is the electrical
equivalent of momentum. So if you're familiar with momentum, essentially,
this is that idea that you get a you know,

(19:57):
objects in motion tend to stay in motion. So let's
say you've got a large mass moving at a particular velocity.
It has a certain amount of momentum and you have
to overcome that momentum to slow down and stop that uh,
that that mass. So it's the same type of thing
with inductors, except we're talking about the electrical equivalent of momentum.

(20:17):
We're talking about the flow of electricity. So again going
back to the water analogy, Let's say that you've got
a water hose, a really long one, several hundred feet long,
and you've coiled it up so it's in a nice
long coil and it's filled with water. There are gallons
of water inside this hose, and the end of the

(20:39):
hose is tilted at such an angle so the water
is not just flowing right out. You put a plunger
into the other end and you start to press on
the plunger to push the water out. Now, all of
that water is not just going to simultaneously start to
move together. It actually is going to take some time
for the pressure you are applying to exert enough force

(21:01):
to push the water out to overcome the inertia within
that coil of water hose. And once you get that
water coming out at the speed at which it can
come out and you let go of the plunger, the
plunger is going to continue going down that tube because
of inertia. That's the same sort of thing with inductors,
except instead of water, we're talking about electricity. So coils

(21:24):
of wire will pass D C current but will block
a C current. So in other words, direct current can
flow through an inductor, but alternating current would be blocked
because it cannot flow the opposite way through the coil.
So that makes it the opposite of capacitors. Remember, capacitors
would pass alternating current that can flow straight through, but

(21:47):
would block direct current. Direct current would charge a capacitor
a capacitor, but could not just flow through the capacitor.
In this case, direct current can flow through an inductor,
but a c altering current would be blocked. The standard
unit of inductance is the henry. I wish I could
tell you why, but I honestly don't know. I'm sure

(22:08):
some of you out there, you electricians, are very familiar
with the reason why and could tell me and feel
free to I I honestly do not off hand. No,
the inductance of a coil is indirectly proportional to the
length of the coil, but directly proportional to the cross
sectional area of the wire, So, in other words, the

(22:29):
gauge of the wire is important here. It's also proportional
to the square of the number of turns in the coil,
and it's directly proportional to the permeability of the core material. Now,
the core is whatever this coil is wrapped around. Now
it could be wrapped around air, or it could be
wrapped around something like iron, which is incredibly effective. So

(22:49):
those are that's what we're talking about with the cords,
whatever the wire or is coiled around. So when current
first starts flowing into the coil, the coil wants to
build up a magnetic field. We talked about this again
and again that you start running electricity through a coil
of wire that's coiled around like an iron core, like

(23:12):
a nail, and you start to you create an electro magnet. Well,
once that field is built. While while the magnetic field
is building, the coil inhibits the flow of current through
the wire, But once the field is built, current can
flow normally through the wire. So if you were to
have an inductor hooked up to a light bulb, let's

(23:34):
say and you flip a switch so that you know,
technically in an electronics we'd say that you close the switch,
so you have created a closed path so electrons can
flow through. The electrons would flow through the inductor, which
would start to build up a magnetic field. So at
first you would get the light bulb coming on. Then
it would start to dim a bit because as that

(23:54):
magnetic field is getting built up the lightbulb, you know,
the electricity would be it did to the light bulb,
it would actually act as sort of a resistor, and
the light bul would start to get dimmer. But then
eventually that that magnetic field would get charged up as
much as it can because it's direct current, not alternating current,
and you would reach a level where it was stabilized.

(24:16):
Current would flow fine. At that point, you could actually
turn off the switch, you can open it. In other words,
the magnetic field around the coil would keep current flowing
through the coil until that magnetic field collapsed. So even
though you turn the switch to off, because you have
an inductor, that light bulb would stay lit until the

(24:40):
magnetic field and the inductor collapsed, in which case it
would stop inducing current to flow through and the light
bulb would go off. So the experience you would have
is turn the switch on, light bulb comes on, light
bulb starts to get dim, light bulb gets bright again,
You turn the switch off, light bulb stays lit for

(25:00):
a while, and then turns off. That's what it would
look like to you, So pretty interesting to me now. So,
an inductor stores energy in its magnetic field, and it
tends to resist any change in the amount of current
flowing through it, thus making it different from capacitors. Because
capacitors store things an electric field, inductor store things energy,

(25:23):
not just things. Capacitor store energy and electric fields, and
inductor store energy and magnetic fields. And capacitors resist changes
to voltage, whereas inductors resist changes to current. So really
interesting about that. We've got more to say in this
classic episode of tech stuff after these quick messages. So

(25:52):
because of this relationship between inductors and capacitors, these two
different components are sometimes referred together as duel components because
they they are opposites that complement one another. The current
in an inductor cannot change instantly the quick current changes
produced the large voltage, and inductors store their energy in
those magnetic fields. That's what sets them opposite of capacitors,

(26:16):
because they are all the opposite of those things. And
you might wonder, well, what are inductors used for. I mean,
that light bulb example seems kind of crazy. Well, they're
used for lots of stuff. For example, if you've ever
gone to uh, like traffic lights, that are the respond
to the presence of vehicles. Most of those are using inductors.
So underneath the pavement where you're driving on top of

(26:39):
you know, there are giant coils of wire, and when
you stop your car at a stoplight that has one
of these systems, your car starts to act as the
core for that inductor loop. You've got this massive amount
of steel that's right there that affects the inductance of
the that cable. You of a meter attached to the

(27:01):
cable that measures the inductance. So when it measures a
change in inductance, that meter knows there's a vehicle at
that location and sends that information to the control unit
for the traffic system and thus changes the traffic cycle
so that you get a green light faster. So if
you're ever at one of those intersections where the the

(27:24):
light cycles depend heavily upon whether or not their cars
present at the intersection, that's generally speaking, what is happening.
You've got these inductors. The inductance changes, sends the message
to the meter, or rather the meter detects the inductor
the change in inductance and then sends that onto the
traffic control system. That will then, at least in theory,

(27:46):
gets you on your way a little faster. So that's inductors.
Now let's take a look at transformers, which are more
than meets the eye. So I'm not talking about autobots
in Decepticon, as much as I would love to do that,
instead of talking about the basic electronic component. So let's
say you've got a single core, like like that iron nail.

(28:10):
Let's say and you put multiple coils of wire over
this same iron core, and then you force a DC
current through one of those coils of wire, not all
of them, just one. Now, as that current charges, it
will induce current to flow through the other coils wrapped
around that same core, and constantly changing the voltage of

(28:32):
that primary coil. The one that you've got attached to
some sort of voltage generator, will cause currents that change
in a similar fashion in the other coils. Now, if
the other coils have more loops than the primary coil,
the voltage will be greater, but the current will be lower.
I'll explain that in a second. So let's say we've
got we'll make it really simple. We'll just do two coils.

(28:55):
Let say we've got an iron core and we've got
a primary wire coiled a fund it ten times, and
we have a second wire coiled in the same direction
around that iron core, but it is coiled twenty times,
and we apply a varying voltage across the primary wire.
The voltage across the second wire will be twice as

(29:15):
much because there are twice as many coils, but the
current will be half as much as that in the
primary coil. And that's because you have to conserve power.
You cannot create or destroy power. You have to conserve it.
And power, like I said earlier, is equal to voltage
times current. So if we double the voltage, but ultimately

(29:36):
the power in the secondary coil has to be the
same as the primary coil, and the only way to
address that is to have the current. So that's you know,
that's what happens. So if the second coil is coiled
in the same direction as the primary, like I was
saying before, the voltage is in the same polarity as

(29:56):
that of the generator the primary coil. If second coil
is coiled in the opposite direction of the primary coil,
then the voltage is in the opposite polarity from the
primary coil. Polarity is really important, but also pretty complicated,
So I'll probably spend another episode to explain that concept

(30:17):
because it's really a bit much to go into right now.
But anyway, this is the basics for power transmission using
alternating current. It's the reason why we have alternating current
distributing our power instead of direct current. So then that
old Tesla versus Edison argument, really i should say Westinghouse

(30:39):
versus Edison argument, where Edison was saying direct current was
best and westing Us was saying no alternating current was best.
The things that let alternating current win out over direct
current where that using transformers you could boost the voltage
to huge high voltage numbers, which were great for power transmission.

(31:01):
You could transmit over vast distances using high voltage wires,
and then you would use other transformers on the opposite
end to step down the voltage until you reach the
level that was safe for homes, which in the United
States is two forty volts. Uh. Now, keep in mind
that when you're talking about transmission voltages, it could be
anywhere between a hundred fifty five thousand to seven d

(31:24):
sixty thousand volts, So we're talking huge differences here, and
it's all because you can use this basic element of
electronics with these transformers to step up or step down
the voltage simply by using different coils along a core.
So that was incredibly useful. You could end up transmitting

(31:46):
power over great distances. Direct current, however, is very different.
It is most efficient if it is close to whatever
the load is on the line. So the load is
whatever the electricity is meant to power. So in the
case of homes, you would want the power plant to
be relatively close to the homes that are receiving electricity.

(32:06):
If you were using direct current, um this is you know,
it would be incredibly useful to have direct current powering
our homes because most of the stuff we have relies
on direct current. It actually has to convert the alternating
current that comes to the house into direct current. You
have these converters that are part of the electronics that

(32:29):
allow it to do that. If you had direct current
being uh supplied directly to your house, you wouldn't need
the conversion part of those devices. However, you wouldn't be
able to transmit it over great distances like you can
with alternating current. So in case you're wondering about the
power grids in the United States. We I mentioned that
you have those those high voltage lines that are carrying

(32:52):
between a d to center sixty volts. When you get
to distribution levels, you step down that voltage to less
than ten thousand volts typically, and then you get to
distribution busses that have transformers that reduce it further to
seven thousand, two hundred volts or less. And then you
have the homes that are connected to a final transformer

(33:13):
that step it down again to the voltage of volts
or so. So incredibly useful and here at how stuff works. Recently,
as of the recording of this podcast, we had a
lovely transformer fire right next to the building we work in,
which cut power to our part of the building for

(33:35):
some time. So if you've ever been near a transformer
when it's blown, it's a pretty spectacular thing. It's usually
lots of sparks and a really loud bang and often
requires the work of dedicated personnel to repair. And it
does also typically mean that you have a loss of
power for at least a localized area. Pretty impressive when

(33:59):
it happens. Luckily, it doesn't happen all that frequently the
electrical storms and areas of or times of great use
can make the more vulnerable. Now let's move on to
semiconductors and how they are used in electronics. So we've
got lots of different uses for semiconductors. I'm going to
talk about two specific ones. There are diodes. Diodes are

(34:21):
really useful. They allow current to flow in only one direction,
so it's like a one way channel or a valve.
So electricity flowing one way is fine, but it cannot
flow back the other way, and semiconductor doping allows for
this to happen. Remember I mentioned earlier. Doping is when
you have introduced impurities into the semiconductor material to give
its specific UH features. So there are two different types

(34:46):
that we're going to talk about. There's IN type layers
of semiconductors, so you can think of that as an
excess of electrons. It has lots of negative electrons that
are just ready to flow out of there. And then
you have of P type layers, and these have electron
holes or at least you know, in other words, of
the capacity to take on electrons. So if you pair

(35:10):
this together, you get what's called a P N diode,
which all only allows electricity to flow in one direction.
It can the electrons can come through UH and flow
to the holes, but they can't go the other way,
so very useful and electronic components where you need to
direct the flow of electricity along a particular path and

(35:31):
prevent it from coming back through that pathway. Transistors are
another type of semiconductor that use a small amount of
current to control a large amount of current. So while
a diode is p n, transistors are either P n
P or N p n, and if you apply an

(35:51):
electrical current to the center layer, which is also known
as the base, electrons will move from the N type
side to the P type side, and that initial small
current allows for much larger current to flow through the
material at that point. So transistors act as switches or amplifiers.
Incredibly useful. So when we talk about transistors in solid

(36:12):
state electronics, these are the things that allow us to
build logic circuits. And it's because we can allow electrons
to either flow or prevent them from flowing. It's also
why things like electron tunneling can be such a problem.
Electron tunneling is a quantum effect, so you can think

(36:33):
of an electron as not really existing in a specific
point in space at any given time, but rather having
the potential to exist in an area of space at
any point in time. So think of it like a
cloud where an electron could be, and that cloud covers
all the potential places the electron could be, and there's

(36:54):
different probability for different parts of the cloud. If your
transistor gates are so small, so narrow, so thin, I
guess I should say not narrow, that the cloud of
potential can overlap the transistor gate. That means there is
the possibility that at some point the electron could exist

(37:15):
on the other side of the transistor gate, even if
the gate never opened. And if there's a possibility, that
means sometimes it does appear on the other side of
the gate. We call it electron tunneling. It's not really tunneling.
It's just if there is the possibility they could be
on the other side, sometimes it is on the other side,
which means that you cannot actually control the flow of electrons.

(37:37):
In that case, it would mean that your transistors would
be ineffective in doing what they're supposed to do. They
wouldn't really be able to act to switches reliably and
you would get errors in your computations. I might work
most of the time and then only some of the
time not work, but even then that's problematic, which is
one of the engineering challenges that transistor designers and multi

(37:59):
around their microprocessor designers encounter all the time, you know.
Finding new materials that are better at acting as transistors
switches it's a big part of it. And coming up
with different architectures to really take advantage of electron flow
is another big part of it, all right. So those
are the basics the basic electronic components that you can

(38:22):
talk about with, you know, if you're looking at it
from a very high level. Obviously there's tons of other
stuff that I didn't get into, and some of it
just requires you to pair up or otherwise put into
series or parallels some of the components I've mentioned to
to get whatever effects you want. I hope you enjoyed

(38:43):
that classic episode of tech Stuff as we covered the
basic components of electronics. It's probably something I'll end up
covering again in various Tech Stuff tidbits episodes where I
really focus on specific components and their place in electronics
and their purpose. Because us you can always do a
better job, right. I mean, I'm always proud of the

(39:05):
work I do, but I also recognize when I could
do it even better, and I think it's about time
I try and do that. If you have suggestions for
topics I should cover in future episodes of tech Stuff,
reach out to me on Twitter to handle for the
show is tech Stuff hs W, and I'll talk to
you again really soon. Text Stuff is an I Heart

(39:30):
Radio production. For more podcasts from I Heart Radio, visit
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