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Uses of Multimeter in Mobile Repairing (English)

Uses of Multimeter in Mobile Repairing (English)


Hello and welcome! I’m sure all of you
understand that in the field of electronics, multimeter is a very
important tool. Without a multimeter you will not be able to measure anything in
the field of electronics. So, come… let’s try and understand how we can use the
multimeter to measure AC and DC voltage and how we can check other electronic
components. Now, as you can see, the device in front of you is a Multimeter. In fact,
this is actually a digital Multimeter. The reason why we call this a digital
Multimeter is because this measures and gives you the results in the form of
digits. As you can see, the digits are very clearly displayed on the screen and
that is one of the reasons why this is called a digital multimeter; because
digits will help you understand the results of whatever you’re checking very
easily. Come.. let’s go and understand how we can use this and what are the safety
features that you need to keep in mind. Now, first of all, you need to understand
what probes are. As you can see, there are two probes which are commonly used with
all multimeters. The first one is a black-colored one; the second one is a
red-colored one and these two probes probes have very specific positions where
you need to place them on the multimeter. Now, the first one is a black probe. The
black probe has to be placed at a point where it is written as COM which
basically signifies a common range. So the black probe has to be placed only in
the common range. Place it there and press it and it will
fit in tightly there. Right above that you’ll see a symbol where it is written as voltage amperior m a, this is where you take readings of voltage,
ampere etc. and you place the red probe here. Press it tightly so it can fit in.
Right above that is another point that you can check higher values of
electricity. However, commonly in a multimeter, we
normally use the red and black probes and that is more than enough to measure
a lot of the electronic components. Now let’s try and understand what are these
other readings that are displayed on the multimeter. Now, on the left-hand side top
left-hand side you’ll see something return as V followed by a dash and a
few dots there. Now, this is the symbol for DC; so on the left-hand side basically
when you turn the knob to the left you will be able to check the DC voltage;
somewhere where the range is between 20 Volts to 1000 Volts; so you can check DC voltage by placing the knob at the respective voltage point. if
you have a smaller voltage to be checked you can place it at 20 Volts
and higher Voltages you can go on up to a 1000 Volts to measure DC Voltage. On the right hand side you see something like a V followed by an ampersand ~ sign
now this is where on the right-hand side you check the AC Voltage; the range is
between 200 Volts to 750 Volts. Now smaller equipments which require 200
Volts or less require the knob to be placed at the 200 volts point. Higher value
equipments can be measured using the 750 Volts point. So these are the two most
important ways of measuring AC and DC voltage using a multimeter. Whenever the
multimeter is not required, the knob should be placed in the off position. Now,
going further down, you’ll see a few more micro readings on the right hand side
which is for smaller readings that can be measured using the multimeter. However, let us focus on only those readings that
are very important that we commonly use using a multimeter. So, let’s go ahead and
try and understand a few more checking components. Now, right below the DC
voltage you’ll see a few Ohm readings given there. This is where you place the
knob to check the value of resistance when you check electronic equipments
which ranges from 200 Ohms to 2000 Kilo Ohms and that is how you turn the knob
there; you can place it at the respective point and check the resistance value. The
next one that we will understand is where the continuity or beep testing
comes. Now, this is a very essential component when you do; this is an essential test when you are doing tracing or testing of mobile PCBs or any PCB for
that matter. This reading or this point is called
the beep or continuity testing and when you place it here and touch the probes
together, you will hear a beep sound. Now the beep sound is very distinct here but let’s
try and understand why what is what is the reason behind this beep sound. Why do
we use this continuity test. Now the reason why we do the beep testing is:
for example when we are checking a wire and you want to check whether the wire
is broken in-between; typically broken wires are called open wires; so if you
want to check whether the wire is broken from inside now you will not be able to
find it out looking at it from the outside. So, in order to check the
continuity, we use to the beep or continuity testing; which means you touch the two
ends of the probe using the two ends of the wire – using the black and red probe
and if you hear a beep sound – which means that the circuit is not open; the wire is
proper. But, if you don’t hear a beep, it means that the circuit is broken
somewhere and you need to fix it now this is also used while doing tracing on
a printed circuit board (PCB) to check whether two points are
connected properly. Now, let’s try and understand how we can check AC and DC
voltage. Now, at home, typically the Voltage that we have is
between 220 or 230 Volts. We will turn the knob now and place it at the 750 Volts
AC point and we will connect this to the main power plug to check the voltage. Now,
in many of the houses its between 220 and 230 Volts voltage is
usually available at the circuit boards. For example, in your room, there are switches which are available
on the board. So typically you also have a plug point in this board. So at this plug point, or at these points you’ll normally get to 220 or 230 Volts electricity at your
house. And whenever you want to check whether you are getting the right
voltage or not, you use a multimeter. Place the knob at the 750 Volts
position and we try and place the two probes in two points on the plug point. Now, as you
can see, the wires are being plugged in into 2 points on your plug point. And this is
exactly where you get 220 to 230 Volts So the probes are placed there and once the
probes are placed there and yes you can see we can see the reading here it shows
244 Volts. Rremember: this is actually in AC voltage.
Typically, in this kind of a voltage, there is always an up-and-down and
sometimes the voltage can go down and sometimes the Voltage is normally high. When the Voltage goes down that’s when you have problems; and your fan and your
lights may not really work properly and that’s called a low-voltage. So you can
always find some differences then so here you saw 244 Volts. Let’s move on and
check DC voltage. So we’re going to be using a battery booster to test this. So
we switched on the battery booster. This is a device that’s used to boost mobile
phone batteries And we’re going to connect the
output wires of this to the probes and we’re going to be testing the voltage of
the output. Now we connect the two output wires of the booster to the two probes
of the multimeter. Make sure that you connect it in the right end so the black
and the black, red in the red and you can see this is around 13.22 Volts; so this
is the DC voltage that we have measured and you can measure DC voltage by
placing the knob at the right position on the DC Voltage side. So,
whenever this is typically help you do your measurements of AC and DC voltage
and whenever you’re done with using the multimeter please switch it off because
typically all these multimeters have a battery inside them So the battery is what gives the power
to the multimeter to display the digits on the screen. So if you keep it switched
on, the battery can drain off very easily and you may not be able to use it when
you need it the most. Hence it is important to ensure that you keep the device
switched off when not in use. So as you can see in this video we tried
understanding what a digital multimeter is, how the probes work , where the probes need to be placed, how we can measure AC and DC voltage, how we can
check continuity. Going forward we’ll see a lot more, will collect a lot more
information about how we use the tool in different streams including mobile
repairing, electronics repairing etc. Thank you very much and see you soon!

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