Electronics 2: Basic Electronics

what intro? So you want to talk about some more electronics? No, but we're gonna no, no, no, this is important stuff. Um So yeah, it's and it's interesting stuff. It is interesting stuff. It's just it's it's definitely. Uh, it's definitely something that that I wish I'd paid more attention to when I was in high school. I understand exactly what

you mean. So last time we talked out electronics, the theory that goes behind electronics, right, we we got into, uh, what we started with adams and and how the negatively charged portion of them, the electron is the basis of electricity, and we got into how they can be used to create circuits and right, and that some materials resist the flow of electrons and others are particularly good at conducting.

And we talked about Benjamin Franklin who gave us the whole concept of currents and described current as moving uh, as positive particles moving towards the negative terminal, which sadly is the opposite of what is happening, is that we have negative particles moving towards a positive terminal. So current goes one way, electron flow goes the other way. And Benjamin Franklin was a brilliant woman izer. I think we also covered that. Well we didn't use that word. No, No,

I think I think I called him a gad about town. No, actually you didn't. Well it was a long time ago anyhow. But yeah, we we got into the basic, the very basics of electricity and UH and how it moves. So now we're gonna talk about circuits. Yes, it's a little more about circuits. So we described last time as a circuit as a kind of a pathway for electrons, a complete closed pathway. UM. And electrons actually have to have

a pathway for them to flow in the first place. Yeah, they can well, I mean they can flow well, well, they can zip around pretty much anywhere because because I think of it this way, plasma that's an ionized gas. That's a gas in which electrons are zipping around all over the place on their own. They become stripped from

their their respective atoms. But you can't really direct that electron flow, so exec to go from point A to point B. Yes, yes, so yeah, the circuit is a way to direct the actual flow of electrons um and you create it. It's like creating a highway system. Really yeah,

for some oftimes particles. So, uh, let's a very basic circuit would be just say, take a battery which has two terminals, positive and a negative terminal, and you attach it to a circuit so that you've got a a wire, well, let's say a copper wire that connects one end of the battery to the other. Will that be a very very basic circuit that doesn't actually do anything other than allow the electrons to move from the negative end to the positive end, which means the current is flowing from

the positive end to the negative end. That's all it's doing. Wouldn't be doing any work, wouldn't really be interesting. All it would really do is slowly kill your battery as the chemicals within it create the electrons necessary to generate the electron flow. Okay, so clearly that wouldn't be enough. You need to add some more elements to it. So let's say you were too uh put a uh what what would you like to put in in our our basic circuit first, and we'll talk about what it does. Okay, Well, um,

a resistor, a capacitor, um switch, anything you want. The switch is the easy part, switch because it's essentially a gateway for the circuit. Yeah. So a switch, if a switch is just a brake somewhere in the circuit really where if you open the switch, then the pathway is interrupted and so electrons can no longer flow along the path. When the switch is closed, the pathway is complete and whole, and then the electrons can flow freely. So there's your switch.

That was easy, all right. Hit me with another one, Come on, come on, okay, let's throw a resistor. Resistor alright, So resistors um resistors are this special kind of device that reduces electron flow. Okay, I'll tell you what. I'll tell you what. Before we add the resistor, let's add something to the circuit like say a lightbulb. Okay, so when you have the battery and you have a light

bulb and you have the switch. So when you open the switch, the circuit completes and the flow of electrons goes through the light bulb and the light bulb comes on. But then if you throw a resistor in there and it slows down the flow of electrons, then theoretically, if I'm not mistaken, the light bulb should dim somewhat. Yeah, well, yeah, because the the it reduces the it's it's they don't they don't block the flow of electrics. There's resisting I mean,

how aptly named can it be? Yeah, and the you might wonder why you would have a resistor in there, but there's lots of reasons. Essentially, what you're talking about whenever you're building any kind of circuit, you're talking about controlling electrons, and electrons behave in a very predictable way. But you may need to throw resistors in there so that you don't overpower a certain part of your circuit um or it may be that you know, it's really

it's really just traffic control. This is really what it comes down to, is that the the amount number and the voltage and current that you are generating maybe too great for parts of the circuits. So the resistors are thrown in there as part of traffic control. That's a very simple way of putting it, and it doesn't get all the subtle nuances that that really come along with resistors. But without really getting into, uh, really the nitty gritty

of electronics, I think it's it serves as a basic foundation. Okay, So do you want to talk about capacitors next, since you've already mentioned them kind of don't belong in our circuit in a way, because I've made too simple a circuit. Yeah, but because you really wouldn't need a capacitor in this case. No, no, no, But a capacitor is uh, it's it's we mentioned it in the last podcast actually because we're talking about capacity tense,

but a capacitor uh involved isn't. What's involved in there is you've got two different plates that are separated by either space or more likely some sort of uh insulating material in between the plates um and the plates hold opposite charges, and they can store a charge and then eventually they can discharge that charge. So they're they're kind of like a battery in a way except that, um, they pretty much discharge all at once. They don't tend

to discharge over time. That and and uh, this capacitor is different from a battery, and that the battery is actually creating electricity through a chemical reaction, and the capacitor you stores and electric Yeah, and uh, capacitors can be polarized. UM, as you point, which, which would you know, permit the flow of electricity in one direction only if you were to reverse the attempt to reverse the flow of electricity

in the other direction. I you don't. You don't want to do that because it would there's a very very good chance that it will explode, which is a bad thing. This is why in Star Trek they always reverse the polarity. I don't know if that's true or not. I just wanted to say it because as soon as you said polarity, that's the first thing I thought of. Well, no, that's that. But that is an important thing though, I mean, do not do not try this at home thing. Don't reverse

the electrical flow through a polar esque capacity. There are other dangerous there are other UM. Capacitors are dangerous in general, there are other things. Yes, we we did mention this in the in the last episode as well. A capacitor, since it does store electric charge and then can discharge it very rapidly, can't does have the potential to be dangerous. Now, a small capacitor is not really that dangerous. It could deliver a shock and you might even you know, might

be a shock strong enough for you to feel. But larger capacitors are are really dangerous, and you find them in electronics that are around you right now, probably things like well old computer monitors, television sets, things like that, they have these capacitors and them that store up a pretty deadly charge and even if the device is not plugged in or turned on at the time, the capacitor can still hold that charge and it could be enough

to cause you injury or even kill you. So that's another good reason to never really mess around with uh with large electronics, even if they're unplugged, and you know, definitely don't do it thinking that you're completely safe from getting shocked, because that's just not the case. It all depends on what's in that circuitry. So, um, let's see, we talked about capacitors, We've talked about resistors, we talked

about switches. There are inducers, which again are that's where you would have a coil of wire that would induce a magnetic field, often used in things like electric electronic motors, also used in UH from what I understand, and those devices that sit under the street of traffic lights. Yeah,

that that's interesting. You're talking about the sensors that can tell if they're is a car at a cross like an intersection, so that knows to turn the left turn light on for example right right, so when your car is there if it has not. Not all intersections have these. There are many different ways that UH that traffic the different traffic devices used to detect whether or not a car is at a traffic stops. Some don't use anything

at all. It's just a simple timer, but on other traffic stops they the it's on a not just a timed system, but it will detect whether or not a car is at a particular location and that will indicate whether or not needs to turn on a turn signal or if it needs to just change the lights so

that the traffic can move in a different direction. The way it does this is you have these um these essentially inducers underneath the street and when your car is on top of them, that's all big metal, you know, big old hunkle metal which can create it can attract with the magnetic field that's created by the inducers, generates the electric current, which then runs to the system and tells the system, Hey, there's a big honking car here that needs to turn. Maybe we should put on that

arrow yep. And then there are diodes, which are another for a form of traffic control because they only permit electricity to flow in one direction. That's a very useful element to have, especially if you're using alternating current, I mean direct current moves in one direction anyway, alternating current. That's when you're starting to look at things like diodes, where because of the nature of the current itself, you need to have some sort of element there to direct

electron flow properly. Uh. There might be some parts of the circuit that it's all right for the electrons to flow one way versus the other way, there's no real difference. And then there are other parts where you may need a diode there to act as kind of a traffic stop. Do you do you want to briefly mention light emitting diodes LEDs, yes, UM so because they are a form of diet. It's a form of diode. It's the little

lights that you see in lots of different things. Like you know, my my phone has an LED at the top that indicates whether or not I've missed a call. By the way, it's probably gonna vibrate any second now as it tells me that I'm supposed to uh to be researching for tweet of the week. But yeah, there are other you know, light emitting diodes that you see all over the place. There televisions that use light emitting diodes UM as the way to generate a picture. It's

a pretty common technology. It's and it's very very simple at the heart of it, but it's it's a definitely important component. But you also have transistors, which are really important.

They can act as both switches and amplifiers, right and again this is more of an alternating current kind of thing, but this transistors are are really that forms the basic of things like the microprocessor UM technology that we all have come to depend upon when it comes to things like you know, computers and smartphones and MP three players things like that. Otherwise they'd be giant because we'd be still using vacuum tubes. So yeah, transistor effectively takes the

takes the place of a vacuum tube. But it is again another traffic control system. And also, like I said, an amplifier, So you may need to um amplify the the flow of electrons in order to make your electronics work properly. Transistors can do that, and uh, they've gotten incredibly small over the years. Like if you ever see a picture of the first transistor, it's a large object. I mean it's it's clunky looking, um and you know,

it definitely does not look elegant at all. Today you have transistors that are measured in nanometers and uh those are really really teeny yeah, one allienth of a meter. I believe that is very very small. So these transistors now you can find billions and billions of them, to quote Carl Sagan on a single processor chip, or at least more than a billion um That's it's it's it boggles my mind. I don't know about anyone else's, but

to think that there are all these teeny tiny uh switches. Now, in this case, we're talking about digital circuits as opposed to analog ones. But um, I mean that's all solid state stuff. So and before we now that we've talked about some basic elements, I mean, there're more that we could talk about. But I also wanted to talk about

the different the three different types of basic circuitry. You've got your basic circuit, which is just a simple pathway, You've got your circuit in series, and you have your parallel circuits. I'm done talking about them now. So a base circuit, you would have a pathway that leads to whatever element that you're trying to power, whether it's a light bulb or what. Let's see, stick with light bug

because it's a very simple example. So with the basic circuit, you would have say, a battery that's providing I'm just gonna be arbitrary here. Let's say three volts of electricity and the the electricity is flowing through uh and powering this one light bulb. Um, when it gets to the other side, you've got zero volts because the the light bulb is consuming that voltage. All right, that it's all

the pressure is going to the light bulb. Okay, got it. Now, Let's say that you hook up a second and third light bulb to that same circuit. So now you've got three light bulbs in series, a series of light bulbs, right, because so the so what you're saying is the electrons flow into the first light bulb and out of the first light bulb to the second, right, So it's you know, going through a series of light bulbs once then too

than three. Yes, now all three of those lightbulbs will light, but they'll each be one third as bright as the one lightbulb basic circuit would be. So light bulb one is going to be the brightest. No, no no, all three will be the same brightness, sharing exactly. So you're so sorry. That's what I was thinking at first, and then that's when you said that I interpreted it differently after apologie.

It was probably the way I worded it. Circuit number one would be three times as bright as circuit number two. Circuit number to would have three times as many lights, but each light would be one third as bright as the light on the first circuit. So essentially they're they're having to share the same number of electrons being generated by the two I'm assuming two batteries because we were saying three volts. That's you know, the average say double

a battery would be one and a half volts. So right, I'm going to say yes, So let's let's talking about that and now parallel circuits. So a serious circuit. That's kind of easy to imagine because you're talking about a loop with three light bulbs along the loop. Now, if you're talking talking about a parallel circuit, you're talking about let's think of a large loop, all right, that starts from the battery, loops out and then comes back to

the battery. So on the far edge, there's one light bulb. Okay, then you you bisect the loop with like a shortcut. Essentially, got it all right. Along that shortcut you have a light bulb, and then you have maybe let's say that it's like the one third the distance out to the to the edge, and then two thirds of the distance out to the edge you have another shortcut. So essentially you've got three pathways that all connect to one major circuit from the positive end of the battery to the

negative end of the battery. This is this is hard to imagine. It's it's a lot easier if you guys look up what a parallel circuit looks like. It's kind of hard to explain. But in this case, uh, you've got you know, it's a little different. It's not you're gonna have a third of the current going through each um light bulb. Okay, the voltage remains the same. The

current will be one third. So in the series, you're talking about the voltage reducing each time it goes through a light bulb, but the current would remain uh constant. In parallel, the current is reduced, the voltage remains constant. Okay, So the pressure is the same, the current is decreased. Yeah, it's a little difficult to imagine. I just tried, by the way, listeners, just so you know, I want to

I want this in the interest of full disclosure. I just attempted to create an analogy, and I got so bogged down in my analogy that I just told Liz to cut that. So if she hasn't cut that, she's been a very bad is But Liz is awesome, so I know she will cut it. Okay. But yeah, so

basic series parallel. And here's the thing is that the different elements we talked about, like resistors and uh and things of that nature, capacitors, they all behave differently depending on whether the circuit is in parallel or is in series, UM, And it's not always intuitive until you really get a real firm grasp on what each element is doing. That's why electronics is is a pretty complex subject in general and very difficult for me to talk about in particular.

If you would like to speak about Middle English literature, that would be awesome because I could let my brain rest. All right, let's see, um trying to go through mine notes here, because you've touched on just about everything I had. Well, we have, we've cut is I mean without getting into to a lot of heavy duty stuff like doping and semiconductors. Yeah, I think I think that would be a good uh stuff to say for the third part we're getting we're

getting up there in time now anyway. And the integrated circuits too, because integrated circuits are very important, especially for a lot of this stuff that we use in our in our homes today. I think we can save that, Yeah, we can save that for electronics three, where we'll talk specifically about the kinds of circuits that we use in computers.

Because a lot of the stuff we've been talking about with resistors and switches things like that, UM, most of that deals with physical circuitry that you would find in uh yeah even right, Yeah, I mean this is this is this is simple stuff. I mean, once you get into the heart of a computer or an electronic device, um,

even it seems like simple, simple electronic devices. Now I'll have chips in them with tons and tons of transistors on them and all kinds of different things, which is wonderful because it makes them very sophisticated, but it also is makes it very difficult to talk about how they're

wide right. Yeah, But we'll we'll tackle uh, digital circuitry in a future podcast, which that'll be and we've talked a little bit about it before with microprocessors and things like that, and I'm actually on fairly firm ground with that. It's funny because you think about it, this this basic electronic stuff, which really should be the foundation of my

knowledge for things like microprocessors. Um, I kind of skipped that and went straight to the microprocessors, and uh it shows yeah, well, um yeah, I mean there there are plenty of other little things we could talk about two like their mists and photo resistors and sure, I mean we could talk about like microphones, which take a physical element converted into electricity, send the electricity through a circuit which then eventually makes its way to a speaker, which

then converts the electrical electrical signal into a physical signal. Again. Yeah, I mean that's that's really when we're talking about when we say that electricity does work. That's kind of the work it it could do. Like it can take sound waves converted into electrical impulses, send it to a speaker, which then converts it back into sound waves. Pretty cool stuff. Yea, you know, the process of changing one type of energy

into the other ran. Yeah, so alternating to direct us that what you're talking about, you know, like transducers and then again talking about transformers, about changing the voltage from high voltage to lower vice versa. Yeah, there are a lot of elements we can get into. So we'll probably be doing these electronics updates occasionally for the rest of our natural lives. Well, if you have something specific to that you'd like us to talk about um with regard

to electronics, please let us know. Yeah, write us an email our addresses tech stuff at how stuff works dot com and we will be glad to tackle it, especially if we can have enough time to make sure we understand it before we start talking about it. Yeah, you know, anything from from some of the stuff that we've already mentioned.

You know, motors, um, you know, changing mechanical I mean electrical electrical energy into mechanical energy, all sorts of stuff like that that we haven't we haven't yet gotten to. If there's something in specific you'd like to know about, please let us know. Yeah, if you want to know, uh, you know how Benjamin Franklin was able to win over the ladies. That's more of us stuff you miss in history class. But you know what, um, I'm willing to look into it. That that is part of the the

uh that that also involves chemistry and you know, attracting. Yeah, that's also getting into science. Then, because we're now you're starting to sound like a quirk. Alright, Well that wraps this up. How's that for a for an outro which a word that does not exist? All right, guys, thanks so much for listening. I hope this wasn't too dry for you. We decided to try and tackle it because we talked about electronics all the time and we kind of take for granted exactly what goes into making them work.

And again we're just hitting the basics now, we haven't even really gotten into the specifics. I mean, I'm sure you've all noticed, so uh, stick with us. We're gonna do some more of these in the future. We're gonna take a break from doing them in the in the near future and do some stuff that makes our brains hurt a little less. So stick with us, and we

will talk to you again really soon. For more on this and thousands of other topics, visit how stuff Works dot com and be sure to check out the new tech stuff blog now on the house Stuff Works homepage. Brought to you by the reinvented two thousand twelve camera. It's ready, are you