Okay, welcome to my, what I call my follow along lab. And what we're going to do here is we're going to up measure voltage. I'm just want to get you guys and ladies of course I keep saying guys, I want to make sure I say ladies, I want to get you comfortable and using a volt meter give you just to get familiar, that type of thing. What I'm going to do is, is made sure that the this meter and like I said earlier, some less expensive meters are up. You'll be able to click on a link, go to Amazon and pick up these components if you so desire. If you want get them at Amazon, I'll again I'll give you my link And we'll go through these.

And we're basically we're going to build upon these. Just as, as if, when I built up, when I put my original courses up, they were very basic. We're gonna we're gonna build upon this. So right now we're gonna start with measuring voltage. Then in the next section, we're going to talk about current, and I'll do one in current and so forth. So we'll build upon this.

So if you're going to stay into the electronic industry, then I suggest that you you know, you need to buy some things here, a meter and some some exotic test equipment. As we go along. I'll mention that and one thing that you should get and I got mine from Amazon, they're they're not very expensive are these type of clip leads here. All right, I use them to click Upon to the meter. There, they've got alligator clips at the end. Here they come in different colors, their assortment of colors.

Right there right there I've got a I've got a white and a green one. Right now the colors are not significant in any way. And again, I'll put a link up for that. Alright, so without further ado, we're going to we're going to measure some voltage and what I'm trying to do here is, is get some, some things that are very easily to get. At some point we're going to build a power supply but just to start off, you can buy these I'll put a link up there but you should be able to get these at any store. They are just basic nine volt batteries and I bought three of them.

Actually, I bought them at the Dollar Tree store up there. So So you can get them. And what we're going to do is we're going to measure some voltage. So if you look at these, these batteries here, all right, let's, let me move these, this here and we'll look at this one there. If you look, I have a negative terminal, which is the larger one, and then I have a positive terminal, which is the smaller one. So we're gonna, we're gonna use that right now.

All right, we're gonna walk, measure this battery voltage here now, and let's get over here and do that. And what I'm going to do is I'm going to turn it on. Well, before I do that, let's connect our voltage source first and then Reason, reason I'm doing that is because when we, when we speak about AC voltage and I go to show you how to measure AC voltage at the very beginning, I'm going to would like you to do it a certain way. Because I mean, we've only got a nine volt battery here, it's not a big deal. But if I'm measuring 120 volts AC, are something greater, we need to use some. We need to be careful.

Alright, so we're going to start here, not that if I do something wrong, I'm going to have a problem probably, most likely we won't. But I just want to get you into the habit of doing that right now. So the first thing we're going to do is we're going to connect our media leads. And we know right here, well, I mentioned before, there's my negative. So I'm going to connect that here to my negative meter lead a common which is black. And then over here we have a plus right And that's going to connect into my red meter lead.

And again, it's you know, if if you were doing this on the bench you may name you may not need these, these alligator clips, but since I'm instructing my need to clip on, I mean, basically, you could just kind of hold the battery and put your two probes there and it would work. Alright, but for demonstration purposes, I'm going to use a clip leads and it's nice for you to have them quite honestly, they've they're not very expensive. I don't know what I paid for these. I think I got like 10 to like two or $3. So it's, it's not that expensive right now. So I'm going to turn the meter on and we're going to go to voltage which is right there.

And we know on this particular meter that when I turn it on, I've got a select DC volts because it automatically defaults to AC volts scale, which we talked about in the last lecture right there see a little small sine wave. So I'm going to hit the select key. And now I know that I'm on DC volts. It's a nine volt battery, what am I reading, I'm reading 10.02 volts. And the reason being on that is, this is a brand new nine volt battery. I'm not draw drawing any current from the battery.

Because this, this meter has a high input impedance, which we'll talk about later. And so I'm getting that which is a voltage above the rated value of the battery. We'll put a load on that in a minute. You'll see it drop. All right, I'll explain that a little bit more. But what I want to do now is is if I reverse my meter leads, and put my red meter lead to my negative terminal here, which is on the green probe, and then take my black meter lead and go to plus.

Let's see what happens. You probably already know. And I get a negative, that's all a negative polarity. All right. So that's that's pretty much it. So let's do this.

Let's put a load on there. And I've already got a 900 ohm resistor. And if you remember, actually to 910 if we remember from our basic circuit theory, class, or lecture, and I'll put it at the end of this demonstration or the next slide. I'll put it up there. What was Be the current flow through this resistor. All right, that resistor there, what would it be?

It would be nine volts divided by 910 ohms. And it's going to be approximately one milli ampere. All right, one milliamp hour. All right. So let's do that. Let's up.

Let's put that across the battery. So what I'm going to do now is I'm going to disconnect here, right? And here's my green lead there, and I'm going to connect one lead on the battery. And then I'm going to disconnect this and I'm going to connect there so now I've got my nine volt battery, direct directly across. Let me move this so so you can see See it a little bit better. All right, here's my green meter lead.

It's connected to one side of the resistor is my white clip lead and it's connected on the other side of the meter. So let's, let's just see what what that will read. Let's see. Okay, so green is negative. I'm putting my my my black probe there. And I am reading let me let me let me do that again.

Hi, I'm reading approximately 9.6 volts. All right, it's still a little high, but that's because it's a new battery. And if I started drawing more current, it would it would go down but it's fine. It's fine. So that's it. That's a nine volt battery, and we just measured it.

Here. Let me let me put this clip lead back. And I'm gonna go on to the next subject. Let me do that one more time for you. All right, actually, I'm going to go right on the terminals right here in the battery. And that's a little bit nicer to stay on, I guess.

So I get 9.67 volts. I, that's the voltage on that battery. All right. So get it if you if you bought your stuff, stop the video. Give it a shot. Okay.

And again, there'll be a listing here for where to get the parts. All right. Okay, let's stop. All right, on that last demonstration. I just wanted to put that up kids. The formular and if you've taken my basic circuit theory course that should be pretty much old hat at this point.

But that's how we found the current nine volt battery right there divided by 910 ohms. Now obviously, when I measured the battery voltage it was a little bit higher. I plugged in the value of the rated value of the battery. In other words, what was stamped on its ideally a nine volt battery. That's what it'll come down to and then have then it'll, it'll just kept the life of the battery, whatever that is okay. And so when I go through my mouth, I get the point 989 milliamp is very close to one milli ampere.

All right, and what I've done here is I've just given you the schematic diagram. So basically I've got my meter my meters across the resistance Is my leads connection right there, again, the terminal on the battery. And when I did it I when I did this slide, I thought it was 9.45 it's actually 9.64 but it doesn't matter. I put 9.45 which is a DC voltage at that point on the meter. And over here, this is sort of like the actual physical representation. This is the schematic representation his my nine volt battery, that's a schematic symbol fart is a schematic symbol for a volt meter, and his the schematic symbol for the resistor.

So that's it. So there you go. Um, if you haven't done it, then rewind the video and go through it. The volt meter a lot, okay. It's probably one of the most common pieces of test equipment that you Use when you get into the electronic industry. Alright, Nuff said.

Let's go on. Okay on this slide here. On the next exercise, I thought it would be fun if we looked at series ating and series of posing. And if you remember I talked about that at one of the very early courses that I put up there. So let's look at this again briefly. Basically, again, we're going to use our nine volt battery.

And as you know, we're going to connect there is a schematic representation of the two batteries. All right, I'm going to take my meter and I'm going to take my common and I'm going to connect it to my negative terminal of one of the batteries. Let me make this a little bit. There we go. We got to make that connection or it won't work and then Now we're going to take our other lead. And we're going to connect it there.

So ideally, what should we read? Well, I have two batteries in series aiding each battery, the posted value on the battery is nine volts, when we actually go to read that we may find it something other than that, but ideally it should be 18 volts. All right. And that's it. So what am I going to say in my meter? 18 volts DC, all right, and that's going to be a DC voltage.

Same thing over here. I've got three batteries in series ating because plus and minus plus and minus, again, going to connect one lead here, going to connect the other lead over there. What am I going to read? I'm going to read 27 volts so my meter should read 27 volts. Now the last one we have two batteries in series ating and one in series opposing. All right, so we got nine plus nine is 18 minus nine is nine volts.

Again, let me stop here, clear the slide off. Okay, these two here are in series ating because I'll go plus and minus. And the last one right here is in series of posing. And that's because we we've got to like terminals there to positive. So again, I'm going to take my meter lead here and go here and go there and see what I read. All righty That's what we got.

So that's pretty much it. And let's see what happens. Okay, what are we going to read here? Well was saying nine volts and we're going to do that. Alrighty. Okay, let's stop here.

We're gonna turn on the video and we're gonna do these. Alright, see over there. Okay, here we go. We're going to do this lab. And here's my batteries, and actually got four but we really only need three. So I'll put that one on.

On the side. I'm going to get a couple of my Yup, clip leads that we spoke about. Here they are. And let's get one more. Alrighty, and so what we're going to do here is I'm going to take these clip Lee And put these batteries and series ating. And we're going to do to just like the first one, let me put this one down here like this.

And I'm just going to connect these series at Now if you'll notice on the last section, I mentioned that we've got a plus here and we've got a negative here. So now I'm just gonna put these in series ating. Got my little clip lead there. I'm going to take my meter probes. Here they are right here. I'm going to turn my meter on to voltage.

Okay, and you remember on this meter here, it automatically comes up in an AC mode. So I'm going to have to use my selector and now I'm on DC and I'm going going to take my black meter lead and go to negative, which is the larger one here. And I'm going to take my other meter lead and I'm going to there and I am reading 19.7 volts. Ideally, it should be 18. But again, as we seen before, there's really no load on this. And when we when we talk about current in the next section, I'll put a current draw on this and you'll see the voltage go down to where it should.

Alright, when they stamp the voltages on some of these voltage sources, they're not exactly they stamp nine volts, but there's a little there's a little bit of slack and there could be I don't know, they really don't tell you but quite honestly, if you buy a battery and the voltage is a little bit higher than what stamped on that's good thing. Because as current draws from the battery, the battery voltage or the terminal voltage on the battery will go down. Alright? And we'll talk about that a little later as we go and talk about circuitry. Okay, but anyways, here we are 19.7. All right.

So I've got 19.7 volts. Alright, ideally, it should be 18. It's a little bit higher, but that that's fine. All right, so let's up. Let's put three in series now.