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Hello, I'm Dr Ferri. 
In this lesson, we will do a Lab Demo for 

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an Introduction of Electrical Components. 
Specifically, look at basic instruments 

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and components that you use to build a 
real circuit. 

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Now, so far in this module, we've covered 
some, some more abstract ideas including 

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resistance Kirchhoff's Laws and 
resistors. 

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Now, we're going to look at real physical 
circuits. 

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So, the lab demo is on introduction of 
electrical components. 

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This experiment is to introduce you to 
some of the basic components of building 

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electrical circuits. 
This meter here is a multimeter, and it 

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has on there a way to measure resistance, 
DC voltage, AC voltage, DC current, and 

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AC current. 
Now, digital mutilmeters are very, very 

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common and you can get them very cheaply 
you know, less than $5 for a digital 

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multimeter. 
And you can use them around the house to 

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make sure you don't have broken 
electrical connections or that you've got 

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a wiring that's, that's doing, that's 
doing what it's supposed to do. 

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For example, if I want to see if I've got 
a electrical connection that's broken. 

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I would check the, the current or the 
resistance. 

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If I have zero resistance, that means 
I'll get a electrical connection. 

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So, for example, these two leads coming 
out. 

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Normally, I'd hook them up between two 
things I'm trying to find the resistance 

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between. 
If I just cross them, that means I've 

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short circuited these out. 
There's zero resistance between them and 

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I'm measuring zero resistance. 
And that's one way I usually check to see 

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if my multimeters got batteries in it. 
Because if I, if I cross the leads I can 

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tell I've got it's, it's working because 
I'm reading zero ohms. 

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Now, let's show a battery. 
This is a battery pack which measures 

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each of these batteries is one and a half 
volts. 

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And I put them in series with one 
another, so the total should be four and 

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a half volts. 
So, if I turn my multimeter to DC voltage 

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and I measure it, I get 4.35 volts. 
And actually, if I reverse this polarity 

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here, change the wires around, I would 
measure minus 4.343 5 volts. 

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So, it's pretty close to 4.5 and not 
exact because the batteries have a little 

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bit of leakage in them. 
And this is a protoboard. 

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A protoboard is really, really useful for 
building circuits. 

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It's because a lot of the electrical 
connections are made for you. 

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If I want to build a circuit, I can build 
components together, and I can cross the 

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wires. 
And it gets pretty messy if I have a lot 

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of crossed wires, because when I cross 
the wires I have to clamp them to make 

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sure they stay put. 
A protoboard board has the connections 

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made behind it. 
So for example, underneath every row of 

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five is connected together. 
So every row, every hole here is 

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connected to the other holes. 
And that's true of all these groupings of 

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five. 
So, if I look at this wire in here versus 

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a wire there. 
And I want to test the resistance, I get 

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zero ohms because they're connected 
together. 

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Similarly, along the side rails, all of 
these groups of ,of holes are connected 

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together. 
So this one and this one are connected 

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together. 
And if I test the resistance, I get down 

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to zero ohms. 
And similarly, this row is connected and 

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over here, this row is connected and this 
row is connected. 

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So, there's four groupings along the 
side. 

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So, every group of five up here is 
connected, but the ones are not connected 

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to each other. 
So this one and this one are in separate 

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rows. 
And if I check the it, it says open loop, 

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they're not connected. 
Now, the next thing I want to show you is 

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resistors. 
This is a common physical resistor, and 

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physical resistors come with color bands, 
so you are able to tell what resistance 

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they are. 
Now if you look up at the color code, 

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you'll see that these colors mean 
something. 

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The first two bands represent the first 
and second significant numbers. 

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And the colors are coded here from black, 
brown, red, orange, yellow, and so on. 

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So, this one, the first two bands are red 
and black. 

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That means that's a two and, and rather 
red and brown. 

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So, that's 2, 1. 
So, that's where we get a 2, 1. 

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And then the third band is orange, that 
means that there's three zeros after it. 

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So, it's 21,000 ohms. 
Now, the fourth band represents the 

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tolerance. 
Resistors are made pretty cheaply, so 

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there's, they're never exactly what 
they're supposed to be. 

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So, whenever they're made there's an, 
there's usually a little bit of tolerance 

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there. 
So, this one is marked as being a 21,000 

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ohm resistor. 
But the actual resistance, if you measure 

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it, is plus or minus 10%. 
There's also a, a gold band which 

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represents 5%. 
Now, going back to this resistor, the 

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first band is a brown and that represents 
the number one. 

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The second band is a black representing 
zero. 

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So I've got a 1, 0. 
And then, followed by the red band 

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meaning two more zeroes. 
So, I've got a 1, 0 and then 0, 0. 

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So it's a thousand ohms, plus or minus 5% 
because that's a gold, gold resistor. 

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Now, let's go ahead and measure it. 
So, this measures out at 989 ohms, which 

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is within the 5% tolerance because 5% of 
1,000 is 50 ohms. 

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So, this is a 989 ohm resistor, even 
though it's marked at 1000 ohms. 

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So, in summary, the lab demo showed us 
examples of physical resistors, and we 

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introduced you to color codes to, to, to 
tell what the actual resistor values are. 

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And we notice that resistors, physical 
resistors are not exact and there are 

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tolerances on them. 
We introduce you to digital multimeters 

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and their use in measuring voltage, 
current, and resistance. 

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And we introduce you to a protoboard, 
often called a breadboard. 

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And it is used for ease of building 
circuits. 

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In the next lesson, we will do another 
lab demo. 

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And that's to introduce you to resistor 
connections and real circuits.