Digital Multimeter Usage
Digital Multimeter Usage TIPS
- Many different multimeters simple to professional
- Brand counts - get one that has a pedigree
- Tools that can troubleshoot many common problems
- Read instructions and work safely
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DEAR TIM: I’m about to buy a digital multimeter to troubleshoot all sorts of electrical issues around my home. I’ll be blunt.
Do you own one, and if so, which one? What do you like about the one you have?
There seems to be a huge difference in these handy devices and I’m very confused as to what to purchase.
I know you can’t tell me everything about these, but can you go over what I can use one for around the house and why there is such a huge disparity in pricing of these tools? Randy P., Akron, OH
DEAR RANDY: I sure can understand your confusion when looking at these products.
Many Different Multimeter Models
If you visit an online retailer that shows all of them next to one another, they pretty much look alike, but the difference in price from the lowest to the highest can vary by 25X or more! It’s natural for you to wonder if there can be such a huge difference inside the tool.
Guess what? the answer is yes. When it comes to digital multimeters you get what you pay for.
I've Got Several
Over the years, I’ve accumulated quite a few digital multimeters. I started off with a beginner's model from Radio Shack.
It’s smaller than a deck of playing cards and has somewhat limited capabilities. I could go on and on about the detailed electrical specifications of multimeters, but it would probably make your head explode.
Free & Fast Bids
What you need to know is that you should get one that’s durable, one that can handle any electrical appliance at your home and one that has a pedigree. The more expensive multimeters can do more.
The digital multimeter I’m now using is a sleek Klein Tools MM700. As you might expect it’s robust and has a full feature set that would impress professional electricians,
HVAC technicians and anyone who tinkers with electronic devices.
Auto Ranging Feature
What I really like about this one is it’s an auto-ranging multimeter. This means it will automatically detect what you want to measure without you guessing the approximate value. I strongly recommend an auto-ranging multimeter for homeowners like you.
Perhaps the most useful thing you’ll do with your new digital multimeter is to check what we call continuity. This refers to checking to see if a wire or circuit is continuous or unbroken.
Here’s a simple example of this. When I take a quarter or a piece of metal, turn on the multimeter, insert the two probes into the proper holes on the tool and touch the quarter with the probes, I hear a nice tone and I see a measurement on the screen. This tells me electricity is flowing through the quarter or metal between the two probes.
Klein MM700 Video Review
Watch this simple video to show a few features of the Klein MM700 Multimeter.
OL = Open Loop
If I had performed the same test but substituted a piece of wire that had a break in it, I would have not heard a thing and my meter would have displayed “OL”. The audible tone in many multimeters is very handy because you can concentrate on what the probes are touching and get the information you need with your ears in some cases.
Jobs For Multimeters
Here’s a few things an auto-ranging multimeter can do around your home that could save you the cost of a service call from an electrician. First things first, when you get your multimeter stop and read the instructions, especially the safety warnings.
Let’s say you have an old-fashioned low-voltage doorbell and it’s not working. You can use the multimeter to see if you’re getting power up to the doorbell switch. If you don’t register power coming to the switch, then you can use the multimeter to check for a break in the wire from the transformer or up to the doorbell.
3-Way Switch Issues
Often people mess up the wires that connect to a 3-way switch. They go nuts trying to figure out what wire connects to what screws on the odd switch. Once again, the multimeter will save you an expensive service call.
You can use it to discover the continuous hot wire that feeds the first switch. Once you know this, it’s pretty easy to get both switches wired the right way.
Bulbs Still Good?
Here’s a simple task many overlook. You can use a multimeter to check to see if light bulbs are burned out.
Realize the small glob of solder at the base of a bulb is connected to one end of the filament. The other end of the filament is connected to the aluminum threads at the base of the bulb.
Turn on the multimeter, touch one probe to the solder glob and one to the threads and check for continuity. If the bulb is still good, you’ll hear a tone if you have my multimeter!
The most common use you may put the multimeter to is to check for live voltage at a switch or an outlet. Follow the instructions that come with the multimeter and avoid working with live circuits.
You can turn off the circuit breaker that provides power to an outlet and then check to see if it is energized. I can do this easily with my MM700 as it has removable shields so the probes can get into the slots of a standard wall outlet. If you’re unsure how to do this, consult with a pro.
Let’s say you think a wall switch or dimmer switch is broken. The multimeter can tell you in a jiffy it still works. Disconnect the switch from the power source and use the continuity tester function.
If the switch is in the on position and you don’t hear an audible signal or readout for continuity, then the switch is probably defective.
Check Car Alternator
If you like working on your cars, a multimeter is invaluable. The alternator on my son’s car went bad and in minutes I used my multimeter to confirm the alternator was not producing the needed power to keep the battery topped off.
Check Surface Temperature!
One thing I love about my Klein Tools MM700 is it also can test the surface temperature of something. It has a really wide range from 0 - 1,500 F! There are countless things around your home you may want to know the temperature of, and most would fall within that range.
Tough & Rugged
I also love how durable my MM700 is. It can handle drops from just over 6 feet and sustain no damage. Remember, read the instruction manual that comes with your new digital multimeter!