How To Use a Multimeter

10 October
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Today I'm sharing how to use a multimeter. But first, what is a multimeter?  

The simple definition is "an instrument for measuring electrical resistance". So without getting all complicated with electrical terms and such, basically it is a little hand-held meter that you can use to test things like batteries, light bulbs, and electrical currents.

In this post, I'll share how to use an analog multimeter to test wiring, how to use a multimeter to test lightbulbs, and how to use a multimeter to test batteries.

I recently shared my new Patio Lighting in the Weekend Yard Work Series and how my dad and I replaced my back porch light with a new light fixture BUT... we had a little bit of a challenge to overcome.

Normally, you will probably know which breaker goes to each of the lights in your house because they are all marked in the panel, right?

Even if they aren't marked, it's easy to determine by just switching off each breaker and if the light goes out then you've got the correct breaker.

However, in my situation, the breaker wasn't marked and the light wasn't working so I couldn't find the correct breaker!

But, there is still a way to figure it out without having to call an electrician, let me show you how 😊

How To Use a Multimeter

How To Use a Multimeter

You can test the wiring after you've removed the old light fixture with a multimeter. 

Here is the light that was not working. I wanted to replace it with a nicer porch light but first, we had to figure out which breaker it went to.

How To Use a Multimeter

How to use a multimeter to test wiring

1. Turn the multimeter to AC - this stands for Alternating Current which is what the wiring in your house is.  
2. Set the dial for the next higher setting than what you are testing for - in the US, most house wiring is 120 volts (240 volts is used on things like dryers and ranges) so on my multimeter, the next higher setting is 250. 

You will notice that the AC settings near the dial are in red so the readings I will read on the analog display will also be in red.

How To Use a Multimeter

3. Remove the light bulb from the socket of your light fixture and touch the test probes from the multimeter to the metal sides where the light bulb would have been - if the pointer on the dial doesn't move then the electricity is not live. If it moves at all then there is some voltage running through the wires in your house to the fixture.

How To Use a Multimeter

Note that this is how it should work! My light was difficult and it wasn't as easy as just unscrewing a light bulb. We couldn't get the cover off the light to get to the bulb so we opted to remove the entire light fixture and test the bare wires.

How To Use a Multimeter

A word of caution if you choose to do it the way we did... Safety first!! 

When you are unsure if the wiring is live do NOT touch the white and black wires together and do NOT touch the wiring with your hands or any metal items like screwdrivers, etc. until you are sure it is not live (no electricity running to it)! The metal probe ends on the multimeter are fine to touch the wires because the parts you hang onto are plastic.

So in my case, once my dad touched the probes to the wires then I started flipping breakers until the pointer on the dial went down to zero, then I knew which breaker controlled that light and I marked it!

How to test lightbulbs with a multimeter

1. Turn the dial on the multi-meter to "Ohm" - this is a unit used in the international system of measurements to measure resistance... whatever right?! Just turn it to Ohm 😁

How To Use a Multimeter

2. Place the red probe on the side of the light bulb where the threads are. 
3. Place the black probe on the end of the light bulb.

If the meter has a reading then the light bulb is good!

How To Use a Multimeter

How to test a battery with a multimeter

This one is especially helpful... testing batteries! No more trying 50 batteries and none of them work!!

1. Turn the multimeter to DC - this stands for Direct Current which is what batteries are.

How To Use a Multimeter

2. Place the black probe on the bottom of the battery.
3. Place the red probe on the end with the raised tip.

How To Use a Multimeter

If the meter has a reading the battery is good!

So THAT is how to use a multimeter! There are many different kinds and brands of multimeters and each one may be a little different so be sure to read the directions before you begin, but this is the basic idea behind them, I hope you found this informative.

If you enjoyed this post, I'd love it if you'd share it!

How To Use a Multimeter

You can purchase analog and digital multimeters very inexpensively on Amazon.
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  1. Very thorough and understandable explanation. I think i understand that confounded little contraption a bit better now!

  2. I love technical articles like this :D Looks like a useful devise to have around, I honestly hadn't heard of it until this post.

    1. Thanks Vanessa, I'm glad you liked the post :o) I feel like so many women think they can't do some things without a man... like replacing light fixtures... I wanted to share how easy it really is!



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