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The multimeter is about to become your best friend when you need to test your bike’s electrical system.
It’s capable of checking something as small as a fuse, or something as large as a whole battery.
But perhaps you’ve unboxed it, and you’re not sure how to use it? Perhaps you’re even worried about electrocuting yourself?
In this blog post, you’ll discover:
- What a multimeter is
- The difference between a multimeter and a test light
- How to set up a multimeter correctly and how to use it
- Some multimeter FAQs
What Is A Multimeter?
A multimeter is an electrical tool used to measure electrical components, such as your motorcycle’s battery or a fuse.
To do these measurements, you use two probes – one for the positive (red) connector and one negative/ground (black) connector.
Multimeter vs. voltmeter
As the name implies, a voltmeter measures voltage (i.e., the difference in electrons between two points) and voltage ONLY.
But do you need to see how much resistance there is in a circuit? Then a voltmeter has little use.
On the other hand, a multimeter can measure voltage, current, and resistance. It’s essentially a 3-for-1 deal.
Multimeter vs. test light
A test light (pictured above) tells you if there’s electricity in a piece of equipment. If there is, a small LED light will light up.
However, it does not tell you how much electricity is in the equipment you’re measuring.
Furthermore, a test light also doesn’t tell you the differences between voltage and current.
Electrical Voltage, Current, Resistance, and Wattage Explained
Are you not too sure about the differences between electrical voltage, current, and resistance?
Check out the article about it right here.
How to set up a multimeter
Depending on the multimeter’s layout, there will be a series of outlets, each one labeled something like:
- “COM” – stands for “Common Ground”
- “VΩmA”
Regardless of what you’re measuring, the black probe ALWAYS goes into the “COM” port.
The red probe goes into the socket with the symbol for the type of electricity you’re measuring:
- V – Voltage
- Ω – Resistance
Now we’re ready to start measuring!
For the sake of simplicity, I’ll use a regular AA battery for this tutorial – although the process is the same for a motorcycle battery.
How to measure voltage with a multimeter
Step 1: Plug the positive (red) probe into the socket with a “V” (for “Voltage”).
Step 2: Turn the center dial from the “Off” position to “V.”
Step 3: Put the positive probe on the positive terminal of your battery. Then, place the negative probe on the negative terminal.
Part 4: Read the reading on the display.
Do you need to measure current?
If so, you should know that you need to break apart the whole circuit so the current can run through the multimeter.
Because of this, it’s much easier to use a current clamp (pictured below) to measure electrical current.
Image by Harke, Public domain, via Wikimedia Commons
How to measure resistance with a multimeter
NOTE: The multimeter tool emits a “test voltage” between the measuring points when measuring resistance. Essentially, the multimeter becomes a part of the circuit.
Because of this, you must disconnect the circuit you’re measuring. If you don’t, the current might not go through the circuit you’re trying to measure, which will give you a false reading.
It’s also good to know that temperature affects resistance – for example, a hot headlight lamp bulb will have more resistance than a cold one.
In this example, I’ll use a 7,5 Amp fuse:
Step 1: Plug the positive (red) probe into the socket with an “Ω” symbol (indicating “Ohm.”
“Ohm” is a unit for measuring electrical resistance).
Step 2: Turn the center dial from the “OFF” position to the “Ω” symbol.
Step 3: Put the probes on the negative and positive terminals.
Or, as in our case, on the two connector prongs of the fuse.
Step 4: Read the display.
How to measure continuity using a multimeter
Before you ask, “continuity” refers to whether or not electricity can flow through the circuit.
On a multimeter, continuity is indicated by a sonar symbol that looks something like this:
NOTE: Before you measure something for continuity, make sure that it’s disconnected from the electrical circuit.
Video Tutorial – Measure for continuity
Multimeter FAQs
Do multimeters need batteries?
The short (and predictable) answer is “it depends.”
Most digital multimeters need batteries, while analog multimeters will not require batteries.
My multimeter, for example, uses a 9 V battery.
Are multimeters dangerous? Can you electrocute yourself using one?
There’s always the risk of an electric shock when you’re working with electricity – and the multimeter is certainly not an exception.
However, the good news is that only the tips of the connectors are metal (which conducts electricity).
The connector handles themselves are plastic (which does NOT conduct electricity).
Therefore, you should be OK as long as you:
- Avoid touching the tips with your hands
- Disconnect the probes and switch off the multimeter it’s not in use
- Put the protective tips on the probes when they’re unplugged.
And if you’re still a bit nervous, wear a pair of rubber gloves to protect your hands even further.
The display shows a negative value – what’s happening?
If you see a negative value on your display, you may have put the positive and the negative probes on the wrong terminal.
I.e., you’ve put the negative probe on the positive connector and the positive probe on the negative connector.
Try switching them around – if you get the same reading, but without a negative value, you’ve done it correctly.
And in case you’re wondering – no – you can’t damage your multimeter or the object you’re measuring by placing the probes on the wrong terminals.
What does the “HOLD” button do?
Sometimes, you might want to read the reading the display without holding onto the probes.
However, the problem is that when you remove the probes, the display reading disappears.
Pressing the “HOLD” button means the reading stays on the display, even after the probes have been removed from the terminals.
