Multimeter Project-Abby Reisner

HOW TO USE A MULTIMETER!

Abby Reisner

WELCOME!

Get ready to get your brain gears spinning!

Have you ever wondered how to use a multimeter?! Well, you’re in the right

place! Off we go to learn about multimeters!

SO WHAT IS A MULTIMETER?A multimeter is an instrument that can

measure voltage, current, AND resistance!

This one has fixed leads…

Leads

Meter

Rotary Switch

Battery Compartmen

t

Input terminal

…and this one doesn’t

Leads

Meter

Rotary Switch

Battery Compartmen

t

Input terminals

WHAT DO ALL THOSE SYMBOLS MEAN?

Warning- see operating manual for instructions

Common input terminal (where you plug it in)

Danger- high voltage terminal

Continuity buzzer (for cable testing and circuit identification)

Diode test (set the rotary switch to this when testing a diode)

AC symbol (alternating current, flow of charge periodically changes direction)

DC symbol (direct current, flow of charge in one direction only

Okay, so how do I choose a setting?

You have to choose

whether you want

voltage, current, or

resistance, as well as AC

or DC! I’ll show you!

CHOOSING VOLTAGE!

Plug the black lead into the COM jack and the red lead into the VΩ jack.

Use the rotary switch to set to desired value.

DC AC

For AC, set the rotary switch to the side that has the V~

For DC, set the rotary switch to the side that has the

Connect the black lead to a voltage source and the red one to a

measuring point. Your value will appear on the screen!

CHOOSING CURRENT!

Plug the black lead into the COM jack and the red lead into the mA or A jack.

Set the rotary switch to the desired current, making sure it’s higher than current expected.

Break the current path and connect the black lead to the more negative side and the red lead to the more

positive side. Turn on the power and your value will appear on the

screen!

Remember…

WHICH IS WHICH?

o Generally, the black lead goes into the COM jack.

o For current, the red lead goes into the mA jack up to 200mA and the 10A jack for anything above that.

o For resistance and voltage, put the red lead into the VΩ jack.

SO MANY NUMBERS!

Here’s how to pick the setting within the chosen thing that you’re measuring:

o Select a setting slightly above the desired number due to internal resistance, which draws some voltage away from the reading.

o If you are unsure of what the range is, choose the highest number possible within the chosen dial.

CHOOSING RESISTANCE!

Disconnect the power. Then, plug the black lead into the COM jack and the red lead into the VΩ jack.

Touch the leads together to short them and make sure the display says 0.

✓

Connect the black and red leads across the circuit and your value will

appear on the meter!

When measuring current, the meter must be connected in

SERIES

If it’s in parallel,

it could short

the path

because the

current would

be too high. This

could damage

the equipment!

When measuring voltage, the meter must be connected in

PARALLEL

This way, all the resistors have the same voltage! If it was in series and a section was cut, the voltage would be effected. But not with parallel!

When measuring resistance, the meter must NOT be connected in

a circuit!

Doing this makes sure that the readings are accurate. If the resistor is in a

circuit, all other things hooked up will effect

the reading as well!

SAFETY!

Don’t be this guy! Make sure you follow all safety precautions so you don’t get hurt.

Always read the manual! It will familiarize you with the things you

need to know to be safe.

Manual

Make sure you are familiar with the equipment you’re working with and the ways to stay safe

while performing the procedure.

I’m learning how to use a multimeter!

Never exceed the input rating of the meter so you don’t

hurt yourself OR the meter!

That’s a good idea!

When using the probes, don’t touch the metal tips! Only touch the insulated part.

If you touch the metal part, you could conduct a current to yourself and possibly get electrocuted! That would be bad

When you’re taking measurements (especially at

high voltage) use the “left hand in the pocket” technique to

protect yourself!

The artist of this painting clearly wanted to convey an important safety fact about

multimeters

Your heart is on the left side of your

body. If you were to get shocked while using your left hand, it could shock your heart

and kill you. Thus, you should use your right hand to take measurements.

Don’t touch the equipment, meter, or test leads while power

is applied when you’re taking measurements in high voltage

equipment.

The multimeter should be wearing this shirt when you’re taking measurements

If you touch the metal part, you could conduct a current to yourself and possibly get electrocuted! That would be bad

Always stand on an insulated surface while working.

Standing on an insulated surface or wearing insulated shoes can help prevent you from getting shocked.

You could stand in this insulated lunchbox…

…or in these insulated rubber boots.

Never work alone!

You should always have someone nearby with you so you can receive aid if something happens to you. It’s helpful if they can perform CPR!

No!

Yes!

Make sure to disconnect the leads before replacing the

batteries in the meter.

If you leave the leads connected, there is still current in the circuit. You don’t want to expose yourself to it by touching the multimeter and the batteries! That would be quite shocking…

Awesome job! You just

graduated from Multimeters-

101!

Now you know all about how to use a

multimeter and how to be safe doing

so!

Your new best friend