1 00:00:05,609 --> 00:00:08,249 Unknown: Okay, welcome to understanding voltage, current 2 00:00:08,279 --> 00:00:13,949 and resistance, part two. Let's go to the next slide. Okay, in 3 00:00:13,949 --> 00:00:18,869 this section here, we're going to talk about AC voltage. And 4 00:00:19,139 --> 00:00:24,449 what we know about AC voltage is that current flows in both 5 00:00:24,629 --> 00:00:25,829 directions. 6 00:00:27,600 --> 00:00:29,370 Alright, the current, 7 00:00:29,700 --> 00:00:36,510 or the voltage brought into our homes is 120 volts RMS volts AC, 8 00:00:37,290 --> 00:00:40,440 and the frequency of 60 hertz. Now, you may not know what that 9 00:00:40,440 --> 00:00:46,020 means now, but when we finished this section, you'll have an 10 00:00:46,020 --> 00:00:50,160 understanding of what that means.

All right. The deal about 11 00:00:50,160 --> 00:00:55,200 AC voltage is it's easy to transport over long distances, 12 00:00:55,500 --> 00:00:59,490 then DC voltage, all right. If you look, I don't know if you've 13 00:00:59,490 --> 00:01:04,710 got that. where you're located, but if you have power poles in 14 00:01:04,710 --> 00:01:08,190 your neighborhood, if you look at some of the power poles, 15 00:01:08,190 --> 00:01:13,410 you'll see these big square boxes in my area here that gray. 16 00:01:14,010 --> 00:01:16,860 I believe in other areas, they may be something other than 17 00:01:16,860 --> 00:01:22,050 gray. But those are transformers.

All right. And 18 00:01:22,080 --> 00:01:26,880 those are used to bring the voltage down because the voltage 19 00:01:26,880 --> 00:01:32,340 coming into that sector is transported over a long 20 00:01:32,340 --> 00:01:37,380 distance. So we have those power trans farmers on top of the pole 21 00:01:37,380 --> 00:01:41,640 and sometimes during the summer, you'll see that sometimes they 22 00:01:41,640 --> 00:01:46,650 explode. Or sometimes they just malfunction because of the heat 23 00:01:46,890 --> 00:01:48,360 and then they have to replace them. 24 00:01:51,810 --> 00:01:52,470 Okay, 25 00:01:52,530 --> 00:01:57,840 what we're showing here is a graphical representation of DC 26 00:01:57,840 --> 00:02:03,810 voltage. That's right.

Represented by this line here, 27 00:02:04,650 --> 00:02:08,850 above the zero line. Now this if this is my zero line, it's a 28 00:02:08,850 --> 00:02:14,130 graph. And obviously, if I go up it's plus. And if I go below the 29 00:02:14,130 --> 00:02:19,920 zero line, it's it's minus. What this is telling me right here is 30 00:02:19,920 --> 00:02:24,750 that it is a positive voltage. And current only flows in one 31 00:02:24,750 --> 00:02:28,980 direction.

And like I'm showing you here, we've talked about 32 00:02:28,980 --> 00:02:33,750 this before. Okay, plus side of the battery negative, so I'm 33 00:02:33,750 --> 00:02:37,530 going from the negative terminal of the battery up through my 34 00:02:37,530 --> 00:02:44,040 resistor load, which RL and into the positive terminal of the 35 00:02:44,040 --> 00:02:49,560 battery. So when I look at something, when I look at the 36 00:02:49,560 --> 00:02:54,750 voltage graphically, okay, this line is above the zero line and 37 00:02:54,750 --> 00:02:58,710 it's telling me that it's a plus voltage. Now, we didn't give it 38 00:02:58,710 --> 00:03:03,450 a value but we Let's say this voltage was five volts, then 39 00:03:03,450 --> 00:03:08,400 this would be five volts here. And that's all there is to it. 40 00:03:12,480 --> 00:03:15,990 Okay, now here is a graphical 41 00:03:15,990 --> 00:03:22,860 representation of AC voltage.

Here's my zero line right there. 42 00:03:23,310 --> 00:03:28,620 Okay? If you notice, half of the watt, half of the waveform goes 43 00:03:28,620 --> 00:03:29,670 above zero 44 00:03:29,970 --> 00:03:30,720 plus 45 00:03:32,160 --> 00:03:37,620 and the other half goes below negative. All right? This is 46 00:03:37,620 --> 00:03:39,330 called a sine wave. 47 00:03:42,180 --> 00:03:43,260 That's one word.

48 00:03:44,220 --> 00:03:50,100 Okay. That's called a sine wave. All right. And basically, this 49 00:03:50,100 --> 00:03:55,470 is this is the wave form that is actually present at your 50 00:03:55,470 --> 00:04:00,960 electrical outlets in your home. Now, let me just stop Hear for 51 00:04:00,960 --> 00:04:08,190 one minute I do not want you do I expect you or am I do not I am 52 00:04:08,190 --> 00:04:14,670 not even going to ask you Do not Do not Do not play with the 53 00:04:14,670 --> 00:04:21,390 voltage coming out of your house sockets. If you do not know what 54 00:04:21,390 --> 00:04:27,480 you're doing, you can get hurt very, very badly.

You could even 55 00:04:27,480 --> 00:04:33,390 die. So please do not play with the voltage coming out of your 56 00:04:33,390 --> 00:04:41,430 house. sockets at home there are 120 volts AC. Alright, it can 57 00:04:41,430 --> 00:04:45,540 kill you if you don't know what you're doing. Nuff said. 58 00:04:46,350 --> 00:04:47,340 Let's go on.

59 00:04:47,970 --> 00:04:55,620 So this sine wave is is an AC waveform. A sine wave is a 60 00:04:55,620 --> 00:05:02,580 replica of an AC waveform I and When I say current flows in both 61 00:05:02,580 --> 00:05:06,420 directions, that's what I'm trying to show here. So in this 62 00:05:06,420 --> 00:05:09,000 part this half of the 63 00:05:09,420 --> 00:05:10,290 cycle, 64 00:05:11,340 --> 00:05:17,970 okay? We have current flow this way, and on this part of the 65 00:05:17,970 --> 00:05:23,280 cycle right here, then we have current flow that way. So 66 00:05:23,280 --> 00:05:26,100 current will flow up and down, 67 00:05:27,390 --> 00:05:31,710 will reverse directions through the load. Okay, 68 00:05:31,979 --> 00:05:36,869 AC waveform, alternating current, that's what we mean 69 00:05:36,869 --> 00:05:44,579 back and forth, back and forth.

And that does it 60 times per 70 00:05:44,579 --> 00:05:48,959 second. All right, so what do I mean by this? Let me clear the 71 00:05:48,959 --> 00:05:54,839 slide and see if I can give you a better idea. Okay, we go from 72 00:05:54,839 --> 00:05:55,709 here 73 00:05:56,880 --> 00:05:57,960 to here 74 00:05:59,070 --> 00:06:01,860 60 times In one second 75 00:06:04,350 --> 00:06:15,960 60 cycles all right 60 cycles all right on this slide here, I 76 00:06:15,960 --> 00:06:19,950 want to mention something and make sure it's clear okay 77 00:06:19,950 --> 00:06:23,490 previously and if you look this should look somewhat familiar to 78 00:06:23,490 --> 00:06:28,170 you, I kind of just repositioned it here. on the previous slide I 79 00:06:28,170 --> 00:06:35,760 stated that from here to here was one cycle. In other words, 80 00:06:35,760 --> 00:06:41,280 we go from, from this point on the waveform to some peak 81 00:06:41,280 --> 00:06:47,940 positive level, down through zero again to some minus maximum 82 00:06:47,940 --> 00:06:53,700 minus level here, back up through zero here, so from so a 83 00:06:53,700 --> 00:06:58,290 cycle is defined from where I begin to where I N so I begin 84 00:06:58,290 --> 00:07:04,440 here and ended there.

And that is one cycle. All right, let me 85 00:07:04,470 --> 00:07:06,120 let me clear this slide off. 86 00:07:07,680 --> 00:07:08,220 All right. 87 00:07:09,330 --> 00:07:14,400 All right. So we have a new term, it's called hurts. 88 00:07:15,420 --> 00:07:15,990 All right?

89 00:07:17,100 --> 00:07:22,350 Hurts. Here it is right here is the derive unit of frequency is 90 00:07:22,350 --> 00:07:28,920 defined as one cycle per second. So when I say 10 hertz, 20 91 00:07:28,920 --> 00:07:34,890 hertz, we're actually meaning 20 cycles per second 30 cycles per 92 00:07:34,890 --> 00:07:41,490 second. What comes out of your home electrical outlet 93 00:07:41,700 --> 00:07:44,100 is 60 hertz. 94 00:07:45,390 --> 00:07:46,170 Okay, 95 00:07:46,410 --> 00:07:52,560 and we know that 60 hertz means 60 cycles per second. So I have 96 00:07:52,560 --> 00:07:59,970 60 of these.

From here. Again, to hear one positive one 97 00:08:00,000 --> 00:08:05,460 Negative and I returned back to zero. I have 60 of them in one 98 00:08:05,640 --> 00:08:06,450 second. 99 00:08:07,530 --> 00:08:08,040 All right. 100 00:08:08,700 --> 00:08:12,450 The reason we use the term hurts, it's honored by this 101 00:08:12,450 --> 00:08:18,660 gentleman here. Henrik Rudolph hertz.

He was a physicist, and 102 00:08:18,660 --> 00:08:22,350 he's the first person to provide conclusive proof that there is 103 00:08:22,350 --> 00:08:27,750 existence of electro magnetic waveforms. And with hertz, 104 00:08:27,750 --> 00:08:31,410 you're going to hear other things like a kilohertz, 105 00:08:31,830 --> 00:08:33,960 megahertz or gigahertz. 106 00:08:34,349 --> 00:08:34,979 Well, 107 00:08:36,600 --> 00:08:42,510 kilohertz is 1000 cycles per second. megahertz is a million 108 00:08:42,810 --> 00:08:48,900 hertz per second and gigahertz is 100 million cycles per 109 00:08:48,900 --> 00:08:52,920 second. And then there's terahertz here, which is, I'll 110 00:08:52,920 --> 00:08:57,930 have to look that up. All right, I'll put it on at the end.

What 111 00:08:57,930 --> 00:09:01,560 what terahertz is it that's really Really a high frequency. 112 00:09:01,860 --> 00:09:06,930 As far as I know, right now, the highest we go is gigahertz. So 113 00:09:09,120 --> 00:09:12,120 that's it. So when I say hertz, 114 00:09:13,020 --> 00:09:13,710 it's 115 00:09:15,180 --> 00:09:19,980 cycles. So when I say 60 cycles per second, it's actually 60 116 00:09:19,980 --> 00:09:24,630 hertz, one hertz equals one cycle. And I hope that cleared 117 00:09:24,630 --> 00:09:30,840 it up.

Let's go on to the next slide. Okay, the next term that 118 00:09:30,840 --> 00:09:36,750 I wanted to find is RMS. Now, when you get into the field, 119 00:09:37,170 --> 00:09:43,200 you'll hear the term are this my RMS voltage is 120 or 120 volts 120 00:09:43,200 --> 00:09:49,680 RMS or 60 volts RMS. Okay. What does this mean? Well, when I 121 00:09:49,680 --> 00:09:55,470 hear the term RMS, it is an AC voltage.

That's number one. All 122 00:09:55,470 --> 00:09:59,970 right, and RMS means root. 123 00:10:01,319 --> 00:10:02,069 Mean 124 00:10:02,550 --> 00:10:09,780 Square, right there. All right. And this is how they derive a 125 00:10:09,780 --> 00:10:15,420 number for a AC waveform. So let's just look at these three 126 00:10:15,420 --> 00:10:18,360 bullets here.

And then we'll go on to the next slide and I'll 127 00:10:18,360 --> 00:10:22,230 explain this a little bit more. Okay, first of all, they take 128 00:10:22,230 --> 00:10:28,950 the square of each individual value, they square it. Alright, 129 00:10:29,580 --> 00:10:33,600 adding the squares, dividing the sum by the number of values is 130 00:10:33,600 --> 00:10:40,200 the mean, or the average. So I, I take many, many points in my 131 00:10:40,230 --> 00:10:46,620 my sine wave many, many, many points. I square them. I add 132 00:10:46,620 --> 00:10:51,150 them up, and then I divide that by the number of points that 133 00:10:51,150 --> 00:10:55,590 I've taken.

Then I take the square root of this value. 134 00:10:56,250 --> 00:10:58,080 That's the RMS value. 135 00:10:58,230 --> 00:10:58,830 All right. 136 00:11:00,659 --> 00:11:06,329 All right. Okay, so let's, let's clean off the slide here and go 137 00:11:06,329 --> 00:11:11,039 on to the next one and, and hopefully we'll get it all 138 00:11:11,039 --> 00:11:15,449 together for you. Okay?

Now what I've showed you here is, is a 139 00:11:15,449 --> 00:11:20,429 sine wave. All right. And one of the things that I want to impose 140 00:11:20,429 --> 00:11:25,169 here is, if I just took the average, the average of the sine 141 00:11:25,169 --> 00:11:26,339 wave would be zero. 142 00:11:26,579 --> 00:11:28,259 Why? Because 143 00:11:28,889 --> 00:11:34,319 this area here is going to equal this area here. Now this area 144 00:11:34,319 --> 00:11:41,459 here is, is minus, in this area up here is plus.

So if I add 145 00:11:41,459 --> 00:11:45,209 them up together, since they're symmetrical, they're the same. 146 00:11:45,659 --> 00:11:50,279 I'm going to get zero. And I can assure you if you grab on to 120 147 00:11:50,279 --> 00:11:55,259 volts AC in ain't gonna feel like zero and we talked about 148 00:11:55,259 --> 00:11:59,969 that earlier. Okay, so basically, we can't do that. 149 00:12:00,029 --> 00:12:05,429 Okay, it won't work. So they came up with this RMS business.

150 00:12:07,109 --> 00:12:07,859 And 151 00:12:09,000 --> 00:12:12,360 if you look, one of the things that we do is we take the 152 00:12:12,360 --> 00:12:15,840 square, well, if I take a negative number, 153 00:12:17,550 --> 00:12:18,960 all right, and I square 154 00:12:18,960 --> 00:12:22,380 it, let's say this is just for talking purposes, that's going 155 00:12:22,380 --> 00:12:25,710 to minus, we have a minus two here, and I'm just, I'm just 156 00:12:25,710 --> 00:12:32,160 pulling this out of my hat. Okay, minus two, squared equals 157 00:12:32,250 --> 00:12:38,220 minus two times minus two, what does that equal to? n equals a 158 00:12:38,220 --> 00:12:42,660 plus four. Okay, when I take a square of two negative numbers, 159 00:12:43,140 --> 00:12:44,460 okay, we get 160 00:12:44,460 --> 00:12:48,630 a positive number. That is just the properties of mathematics. 161 00:12:48,690 --> 00:12:51,390 All right, that's the nature of math, mathematics.

162 00:12:51,719 --> 00:12:52,469 So 163 00:12:53,940 --> 00:12:57,540 what happens is when I take the square of these negative values, 164 00:12:57,810 --> 00:13:02,280 they come positive. All right? So, so we we won't have this 165 00:13:02,280 --> 00:13:06,300 zero business. All right when we when we try to if we tried to 166 00:13:06,300 --> 00:13:07,620 take the mean here. 167 00:13:08,250 --> 00:13:10,050 All right. So 168 00:13:12,059 --> 00:13:15,479 let's erase this slide.

And that's the point I wanted to 169 00:13:15,479 --> 00:13:22,169 make here. So let's go on. And this is just basically what I've 170 00:13:22,169 --> 00:13:25,109 done here is I've just taken a couple of points, 171 00:13:26,280 --> 00:13:27,480 three points, 172 00:13:27,720 --> 00:13:32,040 just to go through the steps and the mechanics of how we get 173 00:13:32,040 --> 00:13:38,730 this. All right, so we take so my value here is this 234. 174 00:13:39,660 --> 00:13:42,090 Okay, and 175 00:13:44,130 --> 00:13:45,630 I take these numbers, 176 00:13:46,860 --> 00:13:51,150 and then I square them. So two squared is four.

Three squared 177 00:13:51,150 --> 00:13:57,330 is nine, four squared is 16. I find them I find the mean, four 178 00:13:57,330 --> 00:14:04,290 plus nine plus 16 divided by three. So if we do the math, 29 179 00:14:04,290 --> 00:14:11,820 divided by three is 9.67. I take that 9.67. And I find the root 180 00:14:11,820 --> 00:14:15,270 which I'm showing you right here. All right, when I take the 181 00:14:15,270 --> 00:14:21,780 root of 9.67, it's 3.11.

And again, you're probably not going 182 00:14:21,780 --> 00:14:27,690 to, I think I've asked you a question if the end of this, but 183 00:14:27,690 --> 00:14:31,650 for the most part, you're not going to have to figure this 184 00:14:31,650 --> 00:14:36,570 out. All right. I mean, as far as being a service technician, 185 00:14:36,570 --> 00:14:41,010 or even an engineer, then you're not going to have to figure this 186 00:14:41,010 --> 00:14:42,990 out. You're gonna, they're gonna, there's going to be a 187 00:14:42,990 --> 00:14:49,950 voltage that's going to be delivered to you. And you're 188 00:14:49,950 --> 00:14:55,260 going to know what the value is. Alrighty, so that's it on this I 189 00:14:55,290 --> 00:14:59,970 again, I just wanted you to see the mechanics on how we get to 190 00:15:00,000 --> 00:15:06,570 RMS voltage.

And if you have any questions, or would like to talk 191 00:15:06,570 --> 00:15:09,240 about it, you know how you can do that. I've preached that at 192 00:15:09,240 --> 00:15:16,080 the beginning here. So let's go on to the next slide. And this 193 00:15:16,080 --> 00:15:19,590 brings us up to this slide understanding voltage, current 194 00:15:19,590 --> 00:15:24,960 resistance. I've put a sine wave up here. All right, and we're 195 00:15:24,960 --> 00:15:27,240 just cutting some of these things I've mentioned some of 196 00:15:27,240 --> 00:15:30,990 them are new.

Alright, if you look at this sine wave, okay, 197 00:15:30,990 --> 00:15:35,190 here's my beginning. And here's my end. That's one cycle. All 198 00:15:35,190 --> 00:15:41,010 right, now we have this AC wave form right here. first bullet, 199 00:15:41,370 --> 00:15:48,000 is 120 volts RMS at 60 hertz. All right.

So we know that 200 00:15:48,000 --> 00:15:51,600 that's the value of this waveform. We know what the 201 00:15:51,600 --> 00:15:57,330 magnitude of voltage is, in terms of RMS and we know how 202 00:15:57,330 --> 00:16:05,910 many cycles per second That this is going to revolve in 60 hertz. 203 00:16:05,910 --> 00:16:09,330 And we talked about that before too. But there's a couple of 204 00:16:09,330 --> 00:16:15,750 more items here that I want to talk about. And the first one is 205 00:16:15,780 --> 00:16:19,800 is peak voltage. Alright, so what do I mean by peak voltage?

206 00:16:19,800 --> 00:16:24,960 Well, I shown you this right here, peak voltage is from my 207 00:16:24,960 --> 00:16:31,110 zero reference line to the top of the waveform that is my peak 208 00:16:31,110 --> 00:16:37,590 voltage. Now, if I give you an RMS voltage, I can find the peak 209 00:16:37,590 --> 00:16:45,000 voltage by multiplying 1.414 times the RMS that is going to 210 00:16:45,000 --> 00:16:49,680 give me my peak voltage. All right, we also have another term 211 00:16:49,680 --> 00:16:54,450 here called peak to peak voltage and, and I'm showing you would 212 00:16:54,450 --> 00:16:58,950 peak to peak voltages right here. It's from my most negative 213 00:16:58,950 --> 00:17:04,860 portion of myself. Wave two, the most positive peak of my sine 214 00:17:04,860 --> 00:17:07,680 wave. All right, I show you right here, it's peak to peak 215 00:17:07,680 --> 00:17:13,890 voltage.

What is that peak to peak voltage equals 2.8 to eight 216 00:17:13,920 --> 00:17:20,190 times RMS, or two times peak voltage. All right, alright. 217 00:17:20,850 --> 00:17:23,130 I can also go the other way. 218 00:17:24,479 --> 00:17:27,389 If I know what my peak voltage is, 219 00:17:30,270 --> 00:17:37,890 I can multiply that by point 707. And I get my RMS voltage. 220 00:17:38,070 --> 00:17:40,800 Now, what are they looking at this one of the things that I 221 00:17:40,830 --> 00:17:44,790 that I didn't do is, what if I just give you the peak to peak 222 00:17:44,790 --> 00:17:48,660 voltage and ask you for the RMS Well, 223 00:17:49,680 --> 00:17:51,510 I take the peak to peak voltage, 224 00:17:51,900 --> 00:17:56,880 divide that by two, which will give me my peak voltage.

And I 225 00:17:56,880 --> 00:18:01,380 multiply that by my RMS which is point seven. Oh Seven. And 226 00:18:01,380 --> 00:18:01,860 that's 227 00:18:03,570 --> 00:18:05,970 how I get my RMS voltage. All right. 228 00:18:07,470 --> 00:18:11,310 All right, what what are these things down here? One over T 229 00:18:11,310 --> 00:18:17,310 equals F and one over F equals T. Okay.

Well, let me let me 230 00:18:17,310 --> 00:18:24,510 clear the slide here. And then we'll explain that to you. Okay, 231 00:18:24,540 --> 00:18:29,940 so what does this mean? Well, one over T or one over time 232 00:18:29,970 --> 00:18:36,660 equals frequency, and one over frequency equals time. Now from 233 00:18:36,660 --> 00:18:41,160 the previous slides, we know that the frequency is the number 234 00:18:41,160 --> 00:18:45,570 of cycles per second. That is measured in hertz.

235 00:18:46,350 --> 00:18:46,950 All right. 236 00:18:48,270 --> 00:18:53,310 So what if we want to know the time 237 00:18:54,180 --> 00:18:55,440 of one 238 00:18:55,620 --> 00:19:00,540 cycle? In other words, what I've told you before, up here is We 239 00:19:00,540 --> 00:19:06,720 have 60 of these from here to here in one second. Well, what 240 00:19:06,720 --> 00:19:10,530 if I want to know the time for, and we'll get into this later. 241 00:19:10,740 --> 00:19:15,390 But there may be a reason why I want to know the time of one 242 00:19:15,390 --> 00:19:24,480 cycle. This is what I do.

One over 60 equals the time of that 243 00:19:24,480 --> 00:19:31,350 cycle. So let's see what that is. And that equals zero dot 244 00:19:32,580 --> 00:19:38,130 0167 245 00:19:38,340 --> 00:19:41,130 seconds. Where's my decimal point right there. 246 00:19:43,560 --> 00:19:44,280 And 247 00:19:45,690 --> 00:19:47,280 what is that? Well, 248 00:19:49,020 --> 00:19:54,300 just very quickly, if we move my decimal point, this way, three 249 00:19:54,300 --> 00:20:00,810 places that is thousands of a second.

So thanks And means 250 00:20:00,810 --> 00:20:05,160 Milly. All right. And I know I had to put up a slide there. 251 00:20:05,160 --> 00:20:08,610 I'll put put one up at the end end here. So you can reference 252 00:20:08,610 --> 00:20:19,740 that. So this time of one cycle is 16.7 milliseconds.

Make sure 253 00:20:19,740 --> 00:20:21,420 I get my decimal point in now. 254 00:20:23,580 --> 00:20:25,950 All right, 16.7 255 00:20:26,310 --> 00:20:27,540 milliseconds. 256 00:20:28,170 --> 00:20:37,980 That's the time it takes one cycle. And Abby, there will be 257 00:20:37,980 --> 00:20:42,720 applications where, especially when you're working with 258 00:20:42,750 --> 00:20:48,000 reactive elements. When I say reactive, I mean capacitors and 259 00:20:48,000 --> 00:20:52,320 inductors where you you might want to know that. So let's 260 00:20:52,320 --> 00:20:53,550 clear the slide.

261 00:20:59,010 --> 00:21:07,170 And so I just did this one for you. One over T equals F. So 262 00:21:07,170 --> 00:21:14,520 let's see. Oh, I'm sorry, let me I did one over F equals T, I'm 263 00:21:14,520 --> 00:21:14,970 sorry. 264 00:21:15,449 --> 00:21:16,499 So let me 265 00:21:17,760 --> 00:21:22,260 let me go on here. So we're going to do this one now. One 266 00:21:22,260 --> 00:21:26,730 over T equals F. So we're going to do this one here.

267 00:21:27,210 --> 00:21:27,780 Now, 268 00:21:29,760 --> 00:21:41,520 we got 16.7 milliseconds or zero dot 0167 seconds. So if I use 269 00:21:41,520 --> 00:21:48,150 this, and in other words, if I Okay, so here, let me do this 270 00:21:48,150 --> 00:21:54,720 one over T equals F. All right. So now T, 271 00:21:55,980 --> 00:21:56,700 down here. 272 00:21:57,420 --> 00:22:07,710 On our last example, here, equaled one zero dot 01 and six, 273 00:22:07,890 --> 00:22:15,570 seven. Now, that's a repeating decimal, it's zero dot 016666. 274 00:22:15,570 --> 00:22:19,320 And it goes on forever.

So when we do the math, okay, it's not 275 00:22:19,320 --> 00:22:23,940 going to come out to exactly. It should come out to 60 hertz, 276 00:22:23,940 --> 00:22:26,700 it's going to be off a little bit, not by much, but it is 277 00:22:26,700 --> 00:22:33,030 going to be off. So now if I, if I just do the opposite. Let's go 278 00:22:33,030 --> 00:22:36,960 to let's go to the calculator here. And again, I'm not showing 279 00:22:36,960 --> 00:22:40,620 you this, we're going to do one, we're going to do one with a 280 00:22:40,620 --> 00:22:44,910 calculator and math, I call it math for math for electronics, 281 00:22:45,180 --> 00:22:49,320 where we're actually going to show you how to do that. So I'm 282 00:22:49,320 --> 00:22:54,960 going to do one divided by zero dot 167 283 00:22:59,070 --> 00:22:59,670 and 284 00:23:00,359 --> 00:23:03,239 one divided by zero dot 285 00:23:06,089 --> 00:23:08,579 167 equals.

286 00:23:09,269 --> 00:23:13,259 Okay, so I get 59.88 287 00:23:14,069 --> 00:23:15,809 cycles or hertz. 288 00:23:23,100 --> 00:23:23,910 And 289 00:23:24,570 --> 00:23:31,710 that's really close to 60 isn't it? 59 dot eight to 60 is it's 290 00:23:31,710 --> 00:23:36,450 close. Very close. It's probably within 1%. So 291 00:23:37,650 --> 00:23:38,520 we're good.

292 00:23:39,480 --> 00:23:41,910 We're good. We've got some problems for you to do at the 293 00:23:41,910 --> 00:23:48,600 end. Again. If you haven't, if you need some clarification, you 294 00:23:48,600 --> 00:23:52,230 know how to get ahold of me. So let's stop here. And let's go on 295 00:23:52,230 --> 00:24:00,810 to the next slide.

Okay, just want to take up A few minutes 296 00:24:00,810 --> 00:24:04,800 here and explain this slide. We're not going to spend a whole 297 00:24:04,800 --> 00:24:08,490 lot of time on this because I'm preparing a course on what I 298 00:24:08,490 --> 00:24:12,900 call math electronics. And we'll expand upon this in a big way. 299 00:24:13,530 --> 00:24:19,500 But just remember one volt here, equals 1000 milli volts. And 300 00:24:19,500 --> 00:24:25,500 then powers of 10. One times 10 to the minus three is milli.

301 00:24:27,030 --> 00:24:28,590 All right, or 302 00:24:28,800 --> 00:24:36,960 one volt equals 1000 micro volts. And micro is one times 10 303 00:24:36,990 --> 00:24:43,290 to the minus six. All right, so what we say is there's 1000 304 00:24:43,290 --> 00:24:48,390 millivolts equals one volt. So we're taking that volt and where 305 00:24:48,810 --> 00:24:56,370 we're breaking that up into 1000 parts. And as far as microvolts 306 00:24:56,400 --> 00:25:03,540 concern there, that means 1 million parts. So if I take one 307 00:25:03,540 --> 00:25:10,710 volt, I can break that up to 1 million parts in one volt.

So if 308 00:25:10,710 --> 00:25:16,350 I have one micro volt, that means I have 1,000,000th of a 309 00:25:16,350 --> 00:25:22,410 volt. If I have one millivolt that means I have one 1,000th of 310 00:25:22,410 --> 00:25:29,160 a volt. All right, so down here now, we're going the other way. 311 00:25:29,460 --> 00:25:37,860 So 1000 volts equals one kilovolt or one kV. All right, 312 00:25:38,100 --> 00:25:48,180 ah, and in powers of 10, that's one times 10 to the third. If I 313 00:25:48,180 --> 00:25:53,610 have one mega volts, that means one mega volts means I have 1 314 00:25:53,610 --> 00:25:59,520 million volts equals one mega volts.

And that's 10 to the 315 00:25:59,520 --> 00:26:04,710 minus plus six. So one times 10 to the plus six. And again, this 316 00:26:04,710 --> 00:26:09,390 is very shot I, this is not the place right here to go into 317 00:26:09,390 --> 00:26:15,480 this, we are going to do a module on math electronics. So 318 00:26:16,740 --> 00:26:21,000 we're going to explain this and many other facets, little bit of 319 00:26:21,000 --> 00:26:24,330 algebra, a little bit of geometry, anything that has to 320 00:26:24,330 --> 00:26:27,840 do with electronics or math to solve an electronic circuit 321 00:26:27,840 --> 00:26:32,610 problem, we'll review and teach in that that module. All right, 322 00:26:32,880 --> 00:26:37,980 what you can see is, when I teach a course, I break that up 323 00:26:37,980 --> 00:26:43,380 into smaller modules. All right, and I recommend that you don't 324 00:26:43,380 --> 00:26:46,860 go on until you completely understand the information, the 325 00:26:46,860 --> 00:26:50,460 material that I give you.

All right. And again, I'm trying to 326 00:26:50,460 --> 00:26:55,410 help you I'm trying to make this as close to a classroom setting 327 00:26:55,410 --> 00:27:00,000 as I possibly can. That's why I give you a number. I give you 328 00:27:00,000 --> 00:27:07,140 Way, contact way to contact me and we'll get through this. 329 00:27:07,320 --> 00:27:10,470 Okay, if you're sincere and you want to put the time in, we'll 330 00:27:10,470 --> 00:27:13,470 get through this. Okay, enough said let's let's go on to the 331 00:27:13,470 --> 00:27:17,880 next slide.

Okay, here are the questions. Let's hit the pause 332 00:27:17,880 --> 00:27:26,160 button. Do the Questions Answers on the next slide. Okay, let's, 333 00:27:26,220 --> 00:27:30,780 let's look at the answer to these problems. The first 160 334 00:27:30,780 --> 00:27:38,070 volts AC RMS, find the peak to peak voltage. It's going to be 335 00:27:38,070 --> 00:27:45,870 169 dot seven eight or 170 volts peak to peak AC.

I would use 336 00:27:45,870 --> 00:27:57,390 this guy here. Next 190 volts AC peak to peak, find peak voltage. 337 00:27:57,630 --> 00:28:03,330 Well that equals 45 watts. peak, all right, if my peak to peak 338 00:28:03,330 --> 00:28:10,920 voltage is 90 volts AC, then one half the peak to peak voltage 339 00:28:11,100 --> 00:28:18,300 equals the peak voltage. So half of 90 is 45. So it's 45 volts 340 00:28:18,300 --> 00:28:19,230 peak AC.

341 00:28:21,390 --> 00:28:23,130 Let's go down to the third bullet 342 00:28:23,520 --> 00:28:29,190 170 volts AC peak, find the RMS 343 00:28:36,090 --> 00:28:37,590 that would be 344 00:28:40,380 --> 00:28:44,220 point 707 times peak voltage. 345 00:28:49,440 --> 00:28:51,510 So I would use that formula there. 346 00:28:52,650 --> 00:28:57,510 Next one, find T for 60 hertz 347 00:29:00,000 --> 00:29:01,320 formula here. 348 00:29:01,950 --> 00:29:06,630 And there's my answer. 16.67 milliseconds. We did that a 349 00:29:06,630 --> 00:29:08,130 couple of slides back.

350 00:29:09,660 --> 00:29:12,450 And the last one, find out 351 00:29:12,480 --> 00:29:18,060 4.8 8.33 milliseconds. And here it is right there. 352 00:29:18,330 --> 00:29:20,040 That's 120 hertz. 353 00:29:20,430 --> 00:29:26,550 So, again, if you have problems, try to do them again, you can 354 00:29:26,550 --> 00:29:30,510 always reach out to me, I'll help you, email, phone, 355 00:29:30,510 --> 00:29:33,810 whatever, I'll help you. Alright, let's go on to the next 356 00:29:33,810 --> 00:29:38,940 slide. And I believe this ends this 357 00:29:39,810 --> 00:29:41,610 module or this section.

358 00:29:42,360 --> 00:29:43,560 So let's go on