WEBVTT - TechStuff Classic: The Basic Components of Electronics 0:00:04.400 --> 0:00:07.760 Welcome to tex Stuff, a production from I Heart Radio. 0:00:12.039 --> 0:00:14.680 Hey there, and welcome to tech Stuff. I'm your host 0:00:14.760 --> 0:00:17.920 job and Strickland. I'mond executive producer with I Heart Radio 0:00:18.000 --> 0:00:21.520 and how the tech area. It is time for a 0:00:21.720 --> 0:00:26.360 classic episode of tech Stuff. This episode originally published on 0:00:26.520 --> 0:00:32.160 June two thousand fifteen. It is titled The Basic Components 0:00:32.280 --> 0:00:35.760 of Electronics. I bet you'll never guess what it's about. 0:00:37.640 --> 0:00:41.000 Don't be alarmed. I'm going in medias race. This is 0:00:41.040 --> 0:00:44.680 the middle of the email here or really the end. Lastly, 0:00:44.800 --> 0:00:47.360 I was hoping in the future to see topics covered 0:00:47.400 --> 0:00:51.360 like how electronics work, transistors, capascitors, chips, etcetera. I worked 0:00:51.360 --> 0:00:53.960 at Radio Shack for five years and got really interested 0:00:53.960 --> 0:00:57.440 in electronic components, but found them pretty confusing. That is 0:00:57.600 --> 0:01:02.120 perfectly understandable. I still have to look up the various 0:01:02.160 --> 0:01:06.120 components and remind myself what each one does, because I 0:01:06.120 --> 0:01:10.119 don't tend to work with electronic circuits that frequently, and 0:01:10.160 --> 0:01:13.840 I know in general what needs to happen, but sometimes 0:01:13.840 --> 0:01:17.640 I forget the specifics because there's a lot of stuff there, 0:01:17.680 --> 0:01:20.800 and if you aren't familiar, if you're not always working 0:01:20.840 --> 0:01:24.080 in that world, it can very easily slip away from you. 0:01:24.200 --> 0:01:27.120 And we are talking about lots of different components that 0:01:27.240 --> 0:01:30.600 you measure using different units, And after a while you 0:01:30.680 --> 0:01:32.720 just start to you know, if you again, if you're 0:01:32.760 --> 0:01:35.039 not just naturally inclined to this kind of stuff, you 0:01:35.040 --> 0:01:37.040 start to pull your hair out. Except in my case 0:01:37.480 --> 0:01:39.360 that's already been done for me, so I just kind 0:01:39.360 --> 0:01:42.360 of rubbed my head. So let's start with the basics. 0:01:43.080 --> 0:01:46.360 And I know this is going to sound incredibly basic, 0:01:46.520 --> 0:01:49.040 but we have to build a foundation before we can 0:01:49.040 --> 0:01:52.480 start talking about the components. So electronics are all about 0:01:52.560 --> 0:01:57.600 leveraging electricity. Not a big surprise, you're you're leveraging electricity 0:01:57.600 --> 0:02:01.280 in order to do something to accomplis something like a 0:02:01.440 --> 0:02:06.440 radio is meant to receive and amplify radio signals and 0:02:06.440 --> 0:02:08.880 and convert them into acoustic signals so that you can 0:02:08.880 --> 0:02:12.760 actually hear them. That that's a simple example. A flashlight 0:02:13.240 --> 0:02:18.480 is meant to channel electricity to end up powering a 0:02:18.600 --> 0:02:21.240 light bulb, which is essentially a resistor. We will talk 0:02:21.280 --> 0:02:25.519 about those that heats up. We're talking about a basic 0:02:25.560 --> 0:02:28.960 incandescent light bulb here um and gives off light as 0:02:28.960 --> 0:02:33.280 a result. That's your basic use of that kind of electronics. 0:02:33.639 --> 0:02:39.119 So we're gonna talk about how electronics control electricity. These 0:02:39.160 --> 0:02:42.760 basic components are all used to do that so that 0:02:42.840 --> 0:02:47.120 you can accomplish whatever the goal of your electronic device is. Now, 0:02:47.160 --> 0:02:50.720 most electronic devices have lots and lots of different components 0:02:50.760 --> 0:02:54.919 to them, sometimes worked in various configurations, whether they're in 0:02:55.040 --> 0:02:57.880 series or in parallel. I'm not going to get into 0:02:57.919 --> 0:03:00.880 all of that because that's be on what I really 0:03:00.919 --> 0:03:05.040 wanted to focus on in this episode. Instead, in this episode, 0:03:05.360 --> 0:03:09.120 I want to talk about the very basic components and 0:03:09.240 --> 0:03:12.519 what they are intended to do. These are the things 0:03:12.560 --> 0:03:15.360 that make up the circuits that you would see in 0:03:15.400 --> 0:03:18.360 physical circuitry. So if you ever have, uh, you know, 0:03:19.200 --> 0:03:21.480 an old electronic device and you were to take it 0:03:21.520 --> 0:03:24.600 apart and you saw all these little weird do dads 0:03:24.680 --> 0:03:27.160 on a circuit board, I'm gonna tell you what those 0:03:27.200 --> 0:03:33.520 do dads do. Dad. Alright, So first we describe an 0:03:33.560 --> 0:03:37.720 electronics materials is having electrons that fall into certain energy 0:03:37.800 --> 0:03:41.240 bands or electronic bands. Now, the two important ones that 0:03:41.320 --> 0:03:44.560 to talk about are the valence band and the conduction band. 0:03:45.200 --> 0:03:47.640 Electrons and the conduction band are able to move freely 0:03:47.680 --> 0:03:50.760 through the material in question. Assuming the conduction band isn't 0:03:50.760 --> 0:03:52.880 totally full, you can think of it kind of like 0:03:52.960 --> 0:03:57.160 a think of it like a nightclub. It's a nightclub 0:03:57.200 --> 0:04:02.480 that's maybe you know, full, so you can still move 0:04:02.520 --> 0:04:06.200 through it freely. Now that nightclubs packed, you're not going anywhere, 0:04:06.280 --> 0:04:08.520 so there has to be you know, almost but not 0:04:08.600 --> 0:04:10.640 quite full for you to be able to move around. 0:04:11.160 --> 0:04:16.120 That's the conduction band. That's the basics of electrical conductivity. UH. 0:04:16.279 --> 0:04:19.279 Whereas the valance band is kind of this um this 0:04:19.279 --> 0:04:22.800 this basic energy level, and there is a gap between 0:04:22.800 --> 0:04:25.680 the valence band and the conduction band. UH. It is 0:04:25.720 --> 0:04:29.200 called the band gap. And depending upon the material, that 0:04:29.240 --> 0:04:31.680 band gap will be of a certain size, and in 0:04:31.720 --> 0:04:35.720 some cases the gap is insurmountable. You cannot get electrons 0:04:36.240 --> 0:04:39.840 from the valence band into the conductance band, and you 0:04:39.880 --> 0:04:43.240 cannot get them to flow, at least not under normal 0:04:43.279 --> 0:04:48.360 operating circumstances. So in that sense, think of you've got 0:04:48.360 --> 0:04:50.520 a like a holding room before you can get into 0:04:50.560 --> 0:04:56.240 the nightclub, and the the doorway going into the nightclub 0:04:56.240 --> 0:04:58.160 has got a big old bouncer, and that big old 0:04:58.160 --> 0:05:01.960 bouncers not letting anyone through that's your band gap. You 0:05:02.160 --> 0:05:06.240 cannot there's no one even collectively, all of you working together, 0:05:06.320 --> 0:05:09.359 you're not gonna be able to budge that bouncer. That 0:05:09.400 --> 0:05:12.200 would be as if you were in a non conducting 0:05:12.279 --> 0:05:14.880 material and I'll get into more of that later. Whereas 0:05:14.880 --> 0:05:18.239 if you're in a room where there's a wide open 0:05:18.320 --> 0:05:20.880 door and you're allowed to go through as long as 0:05:21.120 --> 0:05:24.279 someone else is coming in, that would mean that you 0:05:24.320 --> 0:05:28.039 could flow through properly. You've got you got electrical electrical 0:05:28.080 --> 0:05:31.000 conductivity going on there, and I'll talk more about that 0:05:31.080 --> 0:05:33.880 in a second. I realized this analogy isn't perfect, but 0:05:34.000 --> 0:05:37.279 I'm just trying to simplify things for those who haven't 0:05:37.279 --> 0:05:41.600 really taken this kind of class in physics. So a 0:05:41.680 --> 0:05:45.480 large gap would represent a great deal of energy needed 0:05:45.520 --> 0:05:49.520 to move electrons from the valence band to the conductance band, 0:05:50.480 --> 0:05:53.799 and sometimes that gap is so large as to be 0:05:54.240 --> 0:06:00.360 impossible to cross again under normal operating conditions. So let's 0:06:00.360 --> 0:06:06.920 look at the basic materials that we talk about in electronics, conductors, insulators, 0:06:06.920 --> 0:06:14.120 and semiconductors. Pretty simple to understand. Conductors have high electrical conductivity. 0:06:14.160 --> 0:06:17.479 That means they facilitate the flow of electrons uh. They 0:06:17.480 --> 0:06:20.680 have a nearly full but not completely full conduction band. 0:06:21.000 --> 0:06:24.880 Electrons can move freely through this material in response to 0:06:24.880 --> 0:06:27.960 an electric field applied to that material. So you apply 0:06:28.000 --> 0:06:31.080 an electrical field to this material, it will then allow 0:06:31.080 --> 0:06:34.960 electrons to flow through freely. This is the stuff that 0:06:35.080 --> 0:06:38.080 moves electrons from point A to point B. You apply 0:06:38.160 --> 0:06:41.080 a voltage across it, you get electrons to flow. That's current, 0:06:41.440 --> 0:06:45.680 Although technically current flows from positive to negative as opposed 0:06:45.720 --> 0:06:48.560 to the flow of electrons, which is from negative to positive. 0:06:49.200 --> 0:06:54.960 We can thank lots of early thinkers for that confusion. 0:06:55.520 --> 0:06:58.360 So current flow and electron flow are in opposite directions, 0:06:58.400 --> 0:07:03.080 Thank you, Benjamin Franklin. Uh. Alright, So then you've got insulators. 0:07:03.560 --> 0:07:06.440 These do not have electrons within the conduction band, or 0:07:06.480 --> 0:07:09.680 they have a full conduction band, so again no room 0:07:09.720 --> 0:07:13.000 for electrons to move around, so there are no free electrons. 0:07:13.400 --> 0:07:17.240 They impede the flow of electrons through that material, and 0:07:17.320 --> 0:07:21.560 most solids fall into this category. Metals are uh an exception, 0:07:21.680 --> 0:07:26.640 but most solids are insulators. So at normal operating parameters, 0:07:26.680 --> 0:07:29.080 you wouldn't be able to apply a strong enough electric 0:07:29.160 --> 0:07:33.200 field to make them conduct electricity. So you could apply 0:07:33.240 --> 0:07:36.920 an electric field to these things, but it wouldn't be 0:07:37.000 --> 0:07:40.480 able to jump that gap between the valence band and 0:07:40.520 --> 0:07:44.800 the conductance band, so it would just stop. You wouldn't 0:07:44.800 --> 0:07:47.320 have any electrical flow through that at all. So we 0:07:47.480 --> 0:07:50.720 use insulators for things like insulation on wires where we 0:07:51.160 --> 0:07:56.760 wrapped the wires in that to help prevent leakage or interference, because, 0:07:56.800 --> 0:08:00.160 as we've talked about many times on this show, the 0:08:00.200 --> 0:08:05.400 flow of electricity is also very closely related to magnetism 0:08:05.440 --> 0:08:08.080 and vice versa. So you have to be able to 0:08:08.200 --> 0:08:12.360 limit interference between different wires if you don't want there 0:08:12.400 --> 0:08:17.400 to be that interaction obviously, otherwise you can end up 0:08:17.600 --> 0:08:21.400 causing shorts, which is when you have an unintended connection 0:08:21.440 --> 0:08:24.360 between two different elements of a circuit and it allows 0:08:24.360 --> 0:08:27.440 electricity to pass from one to the other, almost like 0:08:27.480 --> 0:08:29.360 you think of it like a short cut, you know, 0:08:29.360 --> 0:08:32.400 when we say an electrical short and it means that 0:08:32.440 --> 0:08:35.880 the device itself will not work properly because the electricity 0:08:35.920 --> 0:08:38.840 is not flowing through the pathway you had intended it 0:08:38.920 --> 0:08:42.080 to go in. All right, then we've got semiconductors, and 0:08:42.120 --> 0:08:44.880 we'll talk more about them a little bit later, but 0:08:45.000 --> 0:08:48.400 in general, semi conductors have an almost empty conduction band 0:08:48.880 --> 0:08:52.199 and an almost full valence band, and the band gap 0:08:52.360 --> 0:08:56.440 is relatively narrow, so if you don't apply a strong 0:08:56.520 --> 0:08:59.760 enough electric field, it acts as an insulator. But when 0:08:59.840 --> 0:09:02.920 you apply the right amount of energy and electric field, 0:09:02.920 --> 0:09:05.520 it will allow electrons jump from the valence band to 0:09:05.520 --> 0:09:08.520 the conductor band and move freely within the material. You 0:09:08.600 --> 0:09:12.000 do this by doping the material, which is when you 0:09:12.200 --> 0:09:18.160 insert impurities into the semiconductor on purpose. Doping a semiconductor, 0:09:18.240 --> 0:09:24.280 which is all about introducing impurities specifically at at predetermined levels, 0:09:24.920 --> 0:09:27.959 will determine the energy levels required to do this, and 0:09:28.000 --> 0:09:31.200 that's the basis for solid state electronics. We'll get into 0:09:31.240 --> 0:09:35.600 more about semiconductors towards the end of this. And we 0:09:35.679 --> 0:09:39.280 also have to remember voltage and current, something that I 0:09:39.400 --> 0:09:43.600 always have trouble remembering. So voltage is a lot like 0:09:43.679 --> 0:09:46.960 water pressure, all right. That's that's the the amount of 0:09:47.600 --> 0:09:52.320 electrical pressure being applied, and the higher the voltage, the 0:09:52.320 --> 0:09:57.160 more electrons want to move from the concentration of electrons 0:09:57.200 --> 0:10:01.480 to the more positive side. Now, the actual flow of 0:10:01.480 --> 0:10:05.959 electricity is the current, so they are related but not 0:10:06.000 --> 0:10:08.679 the same thing. So voltage and current, and then you 0:10:08.760 --> 0:10:11.280 multiply those two de patent together and you get the power. 0:10:11.679 --> 0:10:15.440 So voltage times current equals power. Alright, So those are 0:10:15.440 --> 0:10:18.520 your basics. Now we're gonna go through and talk about 0:10:18.640 --> 0:10:22.760 the very individual components and what they do. So first 0:10:22.800 --> 0:10:26.840 we have resistors. Resistor does pretty much what it sounds like. 0:10:26.880 --> 0:10:30.640 It does. It resists but does not halt the flow 0:10:30.760 --> 0:10:34.880 of electricity. I'm gonna talk a lot about electricity in 0:10:34.960 --> 0:10:38.160 terms of water because it is a useful analogy, and 0:10:38.360 --> 0:10:42.800 it's also very common to talk about the similarities between 0:10:42.800 --> 0:10:47.000 electricity flowing and water flowing when you're discussing these components. 0:10:47.520 --> 0:10:50.319 So let's say that you have two different pipes. You've 0:10:50.320 --> 0:10:54.040 got a brand spanking new pipe. It's shiny and beautiful 0:10:54.120 --> 0:10:58.880 and free from any any irregularities, and it allows water 0:10:58.920 --> 0:11:02.200 to flow through the minimum of resistance. That water is 0:11:02.240 --> 0:11:05.360 just flowing right through easily. You've got a second, old, 0:11:05.400 --> 0:11:09.440 gnarly pipe, and this one's got calcium build up in it. 0:11:09.559 --> 0:11:11.840 They're all these bumps and stuff on the inside. So 0:11:11.960 --> 0:11:16.600 water actually encounters resistance friction if you will, as it's 0:11:16.600 --> 0:11:20.840 flowing through, and it does not flow through as easily. 0:11:21.440 --> 0:11:24.840 Resistors are like that old gnarly pipe, and they are 0:11:25.400 --> 0:11:30.240 invented on purpose for specific reasons. So why would you 0:11:30.320 --> 0:11:34.520 want to have an electronic component that actually slows down 0:11:34.600 --> 0:11:37.520 or impedes the flow of electricity for some reason. Well, 0:11:38.360 --> 0:11:40.599 sometimes you have to limit the amount of electricity that 0:11:40.640 --> 0:11:43.360 can flow through part of a circuit within a given 0:11:43.400 --> 0:11:47.360 amount of time, sort of like how a faucet going 0:11:47.400 --> 0:11:49.600 back to water, how fauce it can limit how much 0:11:49.600 --> 0:11:52.440 water it can flow through your water pipes into your sink. 0:11:53.160 --> 0:11:56.160 So you wouldn't want just an on off switch for 0:11:56.240 --> 0:11:58.560 the water coming into your home. That water is at 0:11:58.559 --> 0:12:01.320 a much higher pressure, know it's it's a higher pressure 0:12:01.360 --> 0:12:03.800 to deliver the water to your house. And if all 0:12:03.840 --> 0:12:06.040 you had wasn't on off switch and you flipped it, 0:12:06.320 --> 0:12:10.720 you would have water blasting through the pipe according to 0:12:10.800 --> 0:12:12.760 the amount of pressure that was built up behind it. 0:12:13.240 --> 0:12:16.440 That'd be a little bit nerving, especially if you just 0:12:16.440 --> 0:12:19.080 wanted to have a nice, frusty glass water. So you 0:12:19.120 --> 0:12:21.720 want to have some sort of limiter on that to 0:12:21.920 --> 0:12:24.719 control the amount of water that's or the pressure of 0:12:24.760 --> 0:12:27.880 the water that's coming in. So resistors reduced the amount 0:12:27.880 --> 0:12:32.040 of voltage placed on other electronic components within a circuit 0:12:32.440 --> 0:12:34.960 by restricting the amount of current that can flow through 0:12:35.000 --> 0:12:38.800 the resistor. The reason why this is important is that 0:12:39.360 --> 0:12:45.240 we cannot create a battery for every single type of 0:12:45.280 --> 0:12:49.520 electronic device that's out there. It's not practical. So batteries 0:12:49.600 --> 0:12:54.880 different batteries. Different types of batteries have different voltages. So 0:12:55.400 --> 0:13:01.319 you could, in theory, develop a battery specifically for a 0:13:01.360 --> 0:13:05.280 particular type of electronic device that would not require resistors 0:13:05.400 --> 0:13:09.240 because the battery is providing exactly the voltage needed for 0:13:09.440 --> 0:13:13.840 whatever electronic components are in net. But it's not practical 0:13:13.880 --> 0:13:17.480 to do that for everything. We want standardized batteries, and 0:13:17.520 --> 0:13:20.599 then we use things like resistors to help control the 0:13:20.720 --> 0:13:24.280 voltage in those electronic components so that the right amount 0:13:24.320 --> 0:13:27.240 of voltage is applied to those specific parts of the 0:13:27.240 --> 0:13:32.120 electronic circuit, rather than having to have a billion different 0:13:32.120 --> 0:13:36.280 types of batteries. That would not be practical. So there 0:13:36.320 --> 0:13:39.280 are many different types of resistors designed to work on 0:13:39.360 --> 0:13:43.480 specific amounts of electrical power. Now, some have changeable resistor 0:13:43.640 --> 0:13:47.040 values dependent upon the amount of voltage placed across them. 0:13:47.120 --> 0:13:52.560 They're called nonlinear or voltage dependent resistors. Resistor values can 0:13:52.559 --> 0:13:56.400 also change when the temperature of the resistor changes UH. 0:13:56.600 --> 0:13:59.720 Different types of resistors do this. Some can also be 0:14:00.000 --> 0:14:04.360 mechanically adjusted. So it all depends upon what you need 0:14:04.400 --> 0:14:07.120 the resistor form. Why what you needed to do, that's 0:14:07.160 --> 0:14:10.360 what would determine which type of resistor you would use. 0:14:11.000 --> 0:14:13.600 The unit of measurement for a resistor is the ohm 0:14:14.440 --> 0:14:18.400 oh h M. Resistor values are ten percent apart from 0:14:18.440 --> 0:14:22.080 each other, and resistors are color coded with bands of 0:14:22.120 --> 0:14:24.880 color or or rings of color. So the first ring 0:14:24.960 --> 0:14:28.440 represents the first digit of the resistors value. So what 0:14:28.560 --> 0:14:30.160 you would do is you would look at the first ring, 0:14:30.240 --> 0:14:33.040 whatever color it was, you would cross reference that with 0:14:33.640 --> 0:14:38.000 the with a color UH index, and we'll tell you 0:14:38.040 --> 0:14:41.080 what the value of the resistor is for the first digit. 0:14:42.000 --> 0:14:44.640 The second ring tells you the value of the second digit. 0:14:45.120 --> 0:14:48.000 So then you've got the two the two digits that 0:14:48.040 --> 0:14:50.120 are involved. The third tells you the power of ten 0:14:50.200 --> 0:14:54.960 to multiply by, so it might be ten thousand, and 0:14:55.000 --> 0:14:58.200 then you would multiply. Let's say that your first two 0:14:58.200 --> 0:15:00.960 digits are a twenty two and seven, and you would 0:15:01.000 --> 0:15:03.440 multiply that by ten thousand. You have twenty seven thousand homes. 0:15:03.480 --> 0:15:07.000 There and the fourth ring would tell you the tolerance 0:15:07.080 --> 0:15:11.520 of the resistor plus or minus whatever percentage. Uh. So 0:15:11.600 --> 0:15:14.000 the physical size the resistor and the amount of power 0:15:14.040 --> 0:15:16.360 it can handle tends to be proportional. So in other words, 0:15:16.400 --> 0:15:20.080 the larger the resistor, the more power it can handle. 0:15:20.400 --> 0:15:24.920 In general, So those are resistors covers that basic component. 0:15:25.200 --> 0:15:30.280 Now let's move on to capacitors. Alright, So capacitors are 0:15:30.680 --> 0:15:33.760 similar to batteries and that it's a means of storing 0:15:33.920 --> 0:15:40.080 electrical energy, but unlike batteries, instead of creating an a uh, 0:15:40.400 --> 0:15:44.200 electrical flow through a chemical reaction that is steady the 0:15:44.400 --> 0:15:48.960 entire time, it is designed to release a it's it's 0:15:49.160 --> 0:15:55.600 entire stored electrical charge all at once. So let's say 0:15:55.640 --> 0:15:58.680 they've got two leads of a capacitor. You have a 0:15:58.720 --> 0:16:01.680 difference in voltage across us these two leads. That's when 0:16:01.720 --> 0:16:05.240 a capacitor is charged, So one lead has a greater 0:16:05.320 --> 0:16:09.160 build up of electrons than the other lead does. Uh. Now, 0:16:09.200 --> 0:16:12.040 if you were to connect the leads together, you would 0:16:12.040 --> 0:16:15.920 short them. You would have a discharge of that capacitor, 0:16:16.080 --> 0:16:19.200 and the voltage would equalize across the two, so you 0:16:19.240 --> 0:16:22.040 get a release of a quick burst of electricity, so 0:16:22.120 --> 0:16:26.560 capacitors can pass alternating current freely. A C current will 0:16:26.600 --> 0:16:28.880 just pass through a capacitor as if it were not 0:16:29.040 --> 0:16:32.800 really there. Direct current, however, will charge a capacitor. It 0:16:32.800 --> 0:16:36.800 will have that build up of electrons on one side 0:16:37.200 --> 0:16:40.000 while the other side doesn't get that build up of electrons, 0:16:40.040 --> 0:16:43.600 and then you have that difference in voltage. Alternating current 0:16:43.640 --> 0:16:48.640 just will pass back and forth through it without any problems. 0:16:48.640 --> 0:16:52.400 So capacitors contain the same fundamental parts. You have at 0:16:52.480 --> 0:16:57.040 least two conductive plates separated by a non conductive material 0:16:57.120 --> 0:17:00.680 that's the dielectric. The amount of charge held a capacitor 0:17:00.760 --> 0:17:04.000 is measured in units called faret's. But a faret is 0:17:04.119 --> 0:17:08.520 a large amount of capacitance, so large that you don't 0:17:08.600 --> 0:17:12.119 really talk about a ferret. Instead we end up talking 0:17:12.160 --> 0:17:16.000 about micro ferrets, which are about a well, which are 0:17:16.160 --> 0:17:20.639 one million of a ferret, so much smaller. Ferret, by 0:17:20.640 --> 0:17:25.720 the way, not ferret, two different things. Nice Marmot capacitance 0:17:26.000 --> 0:17:29.919 is dependent upon surface area, so it's directly proportional to 0:17:29.960 --> 0:17:33.119 the surface area of those leads, those those capacity plates. 0:17:33.640 --> 0:17:38.040 Um it is indirectly proportional to the distance between the 0:17:38.119 --> 0:17:41.119 plates so the greater the distance between the plates, the 0:17:41.200 --> 0:17:46.760 lower the capacitance. Uh. It's also uh dependent upon the 0:17:46.880 --> 0:17:51.760 dielectric constant of the insulating material. And they are used 0:17:51.800 --> 0:17:54.479 for things that need a quick release of electricity rather 0:17:54.560 --> 0:17:59.000 than a steady flow. So for example, a traditional flash 0:17:59.119 --> 0:18:01.960 on a camera. So you've got an old camera and 0:18:01.960 --> 0:18:05.160 you've got the the the flash, Uh, you know it 0:18:05.200 --> 0:18:07.560 bursts in this quick burst of light. Will It needs 0:18:07.640 --> 0:18:10.560 that quick It needs access to a quick burst of 0:18:10.720 --> 0:18:14.240 electricity in order to do that, and that's what capacitors 0:18:14.240 --> 0:18:16.440 are good for. And it takes some time for the 0:18:16.480 --> 0:18:18.719 capacitors to build up the charge again so it can 0:18:18.760 --> 0:18:21.080 do it another time. That's sort of you know, if 0:18:21.119 --> 0:18:25.000 you're using the old ones, you hear that noise. It's 0:18:25.040 --> 0:18:28.800 the the discharge and then charging of the capacitors that 0:18:29.000 --> 0:18:32.600 require you to take a moment between taking pictures with 0:18:32.680 --> 0:18:38.159 those old style camera flashes. Now, obviously newer ones use 0:18:38.240 --> 0:18:41.760 different a different approach, but you often have capacitors that 0:18:41.840 --> 0:18:46.159 actually provide the electricity for those Now, the voltage of 0:18:46.160 --> 0:18:51.359 a capacitor cannot change instantly, it's important to remember, and 0:18:51.560 --> 0:18:56.720 quick voltage changes in a capacitor produced large current changes. 0:18:57.080 --> 0:19:01.200 Capacitor store energy in an electric field. The reason I 0:19:01.240 --> 0:19:03.600 mentioned all that is because we're now going to talk 0:19:03.880 --> 0:19:09.760 about inductors, and inductors are kind of, um, the opposite 0:19:10.200 --> 0:19:12.919 of capacitors, or really maybe not even opposite is the 0:19:13.000 --> 0:19:15.880 right way of saying it. In many ways that they 0:19:15.920 --> 0:19:19.000 behave in opposite ways than capacitors do. But we'll get 0:19:19.040 --> 0:19:22.120 to that. We'll be back with more of this classic 0:19:22.160 --> 0:19:36.879 episode of tech stuff after this quick break. So basically, 0:19:36.920 --> 0:19:40.639 an inductor at its most basic level is a coil 0:19:40.680 --> 0:19:43.159 of wires, so sometimes we just call them coils and 0:19:43.280 --> 0:19:48.119 not inductors. Uh. They deal with what is the electrical 0:19:48.200 --> 0:19:54.119 equivalent of momentum. So if you're familiar with momentum, essentially, 0:19:54.240 --> 0:19:56.919 this is that idea that you get a you know, 0:19:57.000 --> 0:19:59.400 objects in motion tend to stay in motion. So let's 0:19:59.440 --> 0:20:04.320 say you've got a large mass moving at a particular velocity. 0:20:04.440 --> 0:20:06.800 It has a certain amount of momentum and you have 0:20:06.840 --> 0:20:10.879 to overcome that momentum to slow down and stop that uh, 0:20:10.880 --> 0:20:14.040 that that mass. So it's the same type of thing 0:20:14.119 --> 0:20:17.920 with inductors, except we're talking about the electrical equivalent of momentum. 0:20:17.920 --> 0:20:22.040 We're talking about the flow of electricity. So again going 0:20:22.040 --> 0:20:25.240 back to the water analogy, Let's say that you've got 0:20:25.280 --> 0:20:28.840 a water hose, a really long one, several hundred feet long, 0:20:29.000 --> 0:20:32.400 and you've coiled it up so it's in a nice 0:20:32.480 --> 0:20:36.280 long coil and it's filled with water. There are gallons 0:20:36.480 --> 0:20:39.560 of water inside this hose, and the end of the 0:20:39.600 --> 0:20:41.680 hose is tilted at such an angle so the water 0:20:41.760 --> 0:20:44.440 is not just flowing right out. You put a plunger 0:20:44.480 --> 0:20:47.679 into the other end and you start to press on 0:20:47.760 --> 0:20:51.000 the plunger to push the water out. Now, all of 0:20:51.000 --> 0:20:54.000 that water is not just going to simultaneously start to 0:20:54.119 --> 0:20:56.800 move together. It actually is going to take some time 0:20:57.440 --> 0:21:01.080 for the pressure you are applying to exert enough force 0:21:01.200 --> 0:21:05.240 to push the water out to overcome the inertia within 0:21:05.480 --> 0:21:09.159 that coil of water hose. And once you get that 0:21:09.200 --> 0:21:12.040 water coming out at the speed at which it can 0:21:12.160 --> 0:21:13.920 come out and you let go of the plunger, the 0:21:13.920 --> 0:21:17.840 plunger is going to continue going down that tube because 0:21:17.920 --> 0:21:21.080 of inertia. That's the same sort of thing with inductors, 0:21:21.080 --> 0:21:24.680 except instead of water, we're talking about electricity. So coils 0:21:24.720 --> 0:21:28.199 of wire will pass D C current but will block 0:21:28.520 --> 0:21:31.160 a C current. So in other words, direct current can 0:21:31.240 --> 0:21:36.160 flow through an inductor, but alternating current would be blocked 0:21:36.200 --> 0:21:39.080 because it cannot flow the opposite way through the coil. 0:21:39.800 --> 0:21:43.760 So that makes it the opposite of capacitors. Remember, capacitors 0:21:43.760 --> 0:21:47.240 would pass alternating current that can flow straight through, but 0:21:47.320 --> 0:21:50.480 would block direct current. Direct current would charge a capacitor 0:21:50.520 --> 0:21:52.960 a capacitor, but could not just flow through the capacitor. 0:21:53.320 --> 0:21:56.600 In this case, direct current can flow through an inductor, 0:21:56.680 --> 0:22:00.719 but a c altering current would be blocked. The standard 0:22:00.840 --> 0:22:05.520 unit of inductance is the henry. I wish I could 0:22:05.520 --> 0:22:08.120 tell you why, but I honestly don't know. I'm sure 0:22:08.160 --> 0:22:11.280 some of you out there, you electricians, are very familiar 0:22:11.280 --> 0:22:14.040 with the reason why and could tell me and feel 0:22:14.080 --> 0:22:17.200 free to I I honestly do not off hand. No, 0:22:17.920 --> 0:22:21.240 the inductance of a coil is indirectly proportional to the 0:22:21.359 --> 0:22:25.080 length of the coil, but directly proportional to the cross 0:22:25.200 --> 0:22:29.000 sectional area of the wire, So, in other words, the 0:22:29.040 --> 0:22:32.040 gauge of the wire is important here. It's also proportional 0:22:32.080 --> 0:22:35.000 to the square of the number of turns in the coil, 0:22:35.480 --> 0:22:39.320 and it's directly proportional to the permeability of the core material. Now, 0:22:39.320 --> 0:22:42.560 the core is whatever this coil is wrapped around. Now 0:22:42.560 --> 0:22:44.840 it could be wrapped around air, or it could be 0:22:44.840 --> 0:22:48.760 wrapped around something like iron, which is incredibly effective. So 0:22:49.200 --> 0:22:51.320 those are that's what we're talking about with the cords, 0:22:51.400 --> 0:22:56.399 whatever the wire or is coiled around. So when current 0:22:56.520 --> 0:22:59.560 first starts flowing into the coil, the coil wants to 0:22:59.600 --> 0:23:03.280 build up a magnetic field. We talked about this again 0:23:03.320 --> 0:23:08.439 and again that you start running electricity through a coil 0:23:08.520 --> 0:23:12.439 of wire that's coiled around like an iron core, like 0:23:12.480 --> 0:23:16.800 a nail, and you start to you create an electro magnet. Well, 0:23:16.880 --> 0:23:20.320 once that field is built. While while the magnetic field 0:23:20.359 --> 0:23:22.840 is building, the coil inhibits the flow of current through 0:23:23.040 --> 0:23:26.440 the wire, But once the field is built, current can 0:23:26.480 --> 0:23:30.280 flow normally through the wire. So if you were to 0:23:30.720 --> 0:23:34.360 have an inductor hooked up to a light bulb, let's 0:23:34.359 --> 0:23:37.840 say and you flip a switch so that you know, 0:23:37.920 --> 0:23:40.720 technically in an electronics we'd say that you close the switch, 0:23:40.760 --> 0:23:43.440 so you have created a closed path so electrons can 0:23:43.440 --> 0:23:46.760 flow through. The electrons would flow through the inductor, which 0:23:46.800 --> 0:23:49.560 would start to build up a magnetic field. So at 0:23:49.600 --> 0:23:52.320 first you would get the light bulb coming on. Then 0:23:52.320 --> 0:23:54.520 it would start to dim a bit because as that 0:23:54.600 --> 0:23:58.720 magnetic field is getting built up the lightbulb, you know, 0:23:58.760 --> 0:24:01.080 the electricity would be it did to the light bulb, 0:24:01.080 --> 0:24:03.720 it would actually act as sort of a resistor, and 0:24:03.760 --> 0:24:06.120 the light bul would start to get dimmer. But then 0:24:06.160 --> 0:24:09.360 eventually that that magnetic field would get charged up as 0:24:09.440 --> 0:24:12.919 much as it can because it's direct current, not alternating current, 0:24:13.600 --> 0:24:16.560 and you would reach a level where it was stabilized. 0:24:16.680 --> 0:24:20.439 Current would flow fine. At that point, you could actually 0:24:20.480 --> 0:24:25.639 turn off the switch, you can open it. In other words, 0:24:26.160 --> 0:24:29.440 the magnetic field around the coil would keep current flowing 0:24:29.480 --> 0:24:33.240 through the coil until that magnetic field collapsed. So even 0:24:33.240 --> 0:24:36.560 though you turn the switch to off, because you have 0:24:36.600 --> 0:24:40.280 an inductor, that light bulb would stay lit until the 0:24:40.280 --> 0:24:43.359 magnetic field and the inductor collapsed, in which case it 0:24:43.400 --> 0:24:46.840 would stop inducing current to flow through and the light 0:24:46.840 --> 0:24:50.760 bulb would go off. So the experience you would have 0:24:50.960 --> 0:24:54.520