Download SECOND TERM TEST UNITS ¾ NAME: DATE:

Summarized transcription for YouTube ¨How to Use a Multimetre¨ at
http://www.youtube.com/watch?v=KzjMIcER4EU
Make technology on your time presents:
Weekend projects with Bre Pettis
We are here with our second in a series of skill building workshop here
1st type “You have a solder” and next are...
You are Jose Grant... who is an inventor by day and a hardware hacker by night and he’s gonna
teach us a little bit about multimetres.
Now, Joe ... every electrician, every hardware hacker, everybody I know basically has a
multimetre. What is it?
What is a multimetre?
A multimetre is what I basically like to say is the Swiss Army knife of electronics measurement
tool. It is a unit which will provide you with all sorts of unit measurements. Most meters will provide
you with a way to measure voltage, current, resistance, continuity, and connection between two points,
testing diodes, temperature. Those are the basic functions of a multimetre.
They come in different types. We have a digital multimetre, which is what we are showing
today. Digitally samples signals and gives you measurements. You also have an analogic
multimetre which basically has a gauge like a speedometer of a car that will show you in an
analogic fashion in what the device is measuring.
How do you use it?
What we are going to do next is measure continuity, which is basically measuring a connection
between two points to see if there is a contact there. This is useful to prove a circuit board to see
how the components are connected to each other. We are testing a component to see if there is a
short circuit. We will change our knob to the continuity test mode. The meter will beep and you
will know that it is in continuity test mode. If the meter has an auto power off mode then if the
meter has been turned off you won´t hear the beep. Be careful with that.
We have our connection and we will poke around on the circuit board. When you are testig
continuity you just want to see if the connection is there.
Measuring Resistance with the Multimetre
We will measure the value of resistors which are used to control the amount of current flowing
within a system. You want to know the resistance value, which is in a unit called OHMS. There
are some coloured bars on the resistor. Maybe four or five bars which are coded for the value of
the resistor. It is a secret code for engineers and you can look up the value on a resistor color
code chart.
To measure the real resistance, you want to measure the value of the resistor to be more
accurate.
If you can figure out the resistance with the color bands, why do we measure it? Some variances
occur in resistor bands and it is better to measure it to be closer to accuracy.
How do you do it?
First you set it on the resistance mode. There are different ranges. You need to know the general
range of the resistor before you actually measure it. Put down the probes on the resistor to
measure the kilohms.
If I want to know if it’s a good battery, can I know this with the multimetre?
The multimetre provides you with a voltage measurement function. Take probes and apply them
to the two points on the battery that we want to measure. All you need to do is set the
multimetre to the correct DC measurement voltage. YOU put it to 200 bolts which means you
can test the voltage of anything less than 200. This is the maximum bolt you can set it to on this
multimetre. Typically you would put the black probe to the negative side and the red probe to
the positive. If you reverse them, you will not damage it, but you will get a negative
measurement.
What other things can you do with a multimetre?
You can measure Current as well, which is how much power a circuit is drawing. You need to
be careful because you need to put the probes through the system. Our probe has to go into the
milliamp or amperage setting. If it is beeping something is wrong. It needs to be in the correct
mode. You can damage it when you try to measure current when you are in voltage mode. The
probes need to be in the correct mode.
Further activities
Other interesting websites related with learning how a multimetre works are:
Visual presentation
http://tangentsoft.net/elec/movies/videos/tt06.mov
Good quality image but slow, somehow boring. It is focused on tips about buying and using a
multimetre.
Written documents
http://www.doctronics.co.uk/meter.htm
Explanation about how to use a multimetre. Suitable for 4th ESO and Batxillerat
http://www.electronics-radio.com/articles/test-methods/meters/how-to-use-multimetre.php
Summary of the instruction to use a multimetre.
http://ecmweb.com/mag/electric_basics_digital_multimetres/
Explanation about the basics of a digital multimetre. Suitable for 4th ESO and Batxillerat
http://en.wikipedia.org/wiki/Multimetre
http://www.wikihow.com/Use-a-Multimetre
Interesting webs of the internet Encyclopedia and related sites
How to use a multimetre. Lesson2. Activity 2, provided material
Connections voltage range precaution overloaded probes selecting optimize
multimetre digits number sockets wheel reduced set
1) Turn the __________ on. Insert the __________ into the correct connections this is required because there may be a number of different __________ that
can be used.
2) __________ measurement __________ to the correct type and range for the
measurement to be made. When selecting the range, ensure that the maximum
__________ is above that anticipated.
3) The range on the DMM can then be __________ as necessary. However by
__________ a range that is too high, it prevents the meter being __________.
__________ the range for the best reading. If possible enable all the leading
__________ to not read zero, and in this way the greatest __________ of
significant digits can be read.
4) Once the reading is complete, it is a wise __________ to place the probes into
the voltage measurement __________ and turn the range to maximum
__________.