Hello, I'm Dr Ferri. 
In this lesson, we will do a Lab Demo for 
an Introduction of Electrical Components. 
Specifically, look at basic instruments 
and components that you use to build a 
real circuit. 
Now, so far in this module, we've covered 
some, some more abstract ideas including 
resistance Kirchhoff's Laws and 
resistors. 
Now, we're going to look at real physical 
circuits. 
So, the lab demo is on introduction of 
electrical components. 
This experiment is to introduce you to 
some of the basic components of building 
electrical circuits. 
This meter here is a multimeter, and it 
has on there a way to measure resistance, 
DC voltage, AC voltage, DC current, and 
AC current. 
Now, digital mutilmeters are very, very 
common and you can get them very cheaply 
you know, less than $5 for a digital 
multimeter. 
And you can use them around the house to 
make sure you don't have broken 
electrical connections or that you've got 
a wiring that's, that's doing, that's 
doing what it's supposed to do. 
For example, if I want to see if I've got 
a electrical connection that's broken. 
I would check the, the current or the 
resistance. 
If I have zero resistance, that means 
I'll get a electrical connection. 
So, for example, these two leads coming 
out. 
Normally, I'd hook them up between two 
things I'm trying to find the resistance 
between. 
If I just cross them, that means I've 
short circuited these out. 
There's zero resistance between them and 
I'm measuring zero resistance. 
And that's one way I usually check to see 
if my multimeters got batteries in it. 
Because if I, if I cross the leads I can 
tell I've got it's, it's working because 
I'm reading zero ohms. 
Now, let's show a battery. 
This is a battery pack which measures 
each of these batteries is one and a half 
volts. 
And I put them in series with one 
another, so the total should be four and 
a half volts. 
So, if I turn my multimeter to DC voltage 
and I measure it, I get 4.35 volts. 
And actually, if I reverse this polarity 
here, change the wires around, I would 
measure minus 4.343 5 volts. 
So, it's pretty close to 4.5 and not 
exact because the batteries have a little 
bit of leakage in them. 
And this is a protoboard. 
A protoboard is really, really useful for 
building circuits. 
It's because a lot of the electrical 
connections are made for you. 
If I want to build a circuit, I can build 
components together, and I can cross the 
wires. 
And it gets pretty messy if I have a lot 
of crossed wires, because when I cross 
the wires I have to clamp them to make 
sure they stay put. 
A protoboard board has the connections 
made behind it. 
So for example, underneath every row of 
five is connected together. 
So every row, every hole here is 
connected to the other holes. 
And that's true of all these groupings of 
five. 
So, if I look at this wire in here versus 
a wire there. 
And I want to test the resistance, I get 
zero ohms because they're connected 
together. 
Similarly, along the side rails, all of 
these groups of ,of holes are connected 
together. 
So this one and this one are connected 
together. 
And if I test the resistance, I get down 
to zero ohms. 
And similarly, this row is connected and 
over here, this row is connected and this 
row is connected. 
So, there's four groupings along the 
side. 
So, every group of five up here is 
connected, but the ones are not connected 
to each other. 
So this one and this one are in separate 
rows. 
And if I check the it, it says open loop, 
they're not connected. 
Now, the next thing I want to show you is 
resistors. 
This is a common physical resistor, and 
physical resistors come with color bands, 
so you are able to tell what resistance 
they are. 
Now if you look up at the color code, 
you'll see that these colors mean 
something. 
The first two bands represent the first 
and second significant numbers. 
And the colors are coded here from black, 
brown, red, orange, yellow, and so on. 
So, this one, the first two bands are red 
and black. 
That means that's a two and, and rather 
red and brown. 
So, that's 2, 1. 
So, that's where we get a 2, 1. 
And then the third band is orange, that 
means that there's three zeros after it. 
So, it's 21,000 ohms. 
Now, the fourth band represents the 
tolerance. 
Resistors are made pretty cheaply, so 
there's, they're never exactly what 
they're supposed to be. 
So, whenever they're made there's an, 
there's usually a little bit of tolerance 
there. 
So, this one is marked as being a 21,000 
ohm resistor. 
But the actual resistance, if you measure 
it, is plus or minus 10%. 
There's also a, a gold band which 
represents 5%. 
Now, going back to this resistor, the 
first band is a brown and that represents 
the number one. 
The second band is a black representing 
zero. 
So I've got a 1, 0. 
And then, followed by the red band 
meaning two more zeroes. 
So, I've got a 1, 0 and then 0, 0. 
So it's a thousand ohms, plus or minus 5% 
because that's a gold, gold resistor. 
Now, let's go ahead and measure it. 
So, this measures out at 989 ohms, which 
is within the 5% tolerance because 5% of 
1,000 is 50 ohms. 
So, this is a 989 ohm resistor, even 
though it's marked at 1000 ohms. 
So, in summary, the lab demo showed us 
examples of physical resistors, and we 
introduced you to color codes to, to, to 
tell what the actual resistor values are. 
And we notice that resistors, physical 
resistors are not exact and there are 
tolerances on them. 
We introduce you to digital multimeters 
and their use in measuring voltage, 
current, and resistance. 
And we introduce you to a protoboard, 
often called a breadboard. 
And it is used for ease of building 
circuits. 
In the next lesson, we will do another 
lab demo. 
And that's to introduce you to resistor 
connections and real circuits.