How to use a multimeter – Voltage
Using a multimeter can be a bit scary right? If you put your test probes there, will you get the proper reading? Might you get shocked? The post below is supposed to help out with using a multimeter, or a voltmeter as some call it, to measure voltage.
Resistance and current will be addressed later, this one hopefully is strictly for measuring voltage. As we mentioned before, voltage is the driving force behind the current. Without voltage, our little electron friends don’t move.
Why it’s important to know how to use a multimeter
For one, you’re a person, don’t you want to know how to use one? Also, you may have an issue come up at home or work that you need to solve. Maybe it’s an outlet at home that all of a sudden doesn’t seem to work. Maybe it is the all important coffee maker at work that has no power.
Whatever it is, especially the frickin’ coffee, you have to solve it. With meters being the scary bastards that they are, you have come to the right place. First though…
My disclaimer. Don’t be an idiot. Or a moron. If you read this post and then do something moronic, that’s on you. Always observe electrical safety guidelines, you should never work on anything hot, never reach into an energized panel, etc. If you are choosing to use a multimeter, you are also choosing to on your own.
Let’s say you have an electrical issue going on at home, or even better, one on your trailer in your driveway. The running lights don’t come on maybe. Multimeters are so very handy for troubleshooting btw. The best way to determine some electrical issues is by using a multimeter. By troubleshooting, taking readings, and making changes, you can solve most issues.
Using a multimeter is one of the most basic skills in electronics. Reading a multimeter is not hard but requires some basic knowledge about electricity and electronics.
What is a multimeter?
Multimeters measure an assortment of various electrical properties – voltage, current, resistance (more.) Multimeters are made by Fluke, Black and Decker, Klein, and are used by homeowners, technicians, and pros like electricians and mechanics. Since you invested money into a meter, you’re going to need to know how to use it effectively – and safely. Plus, you again should want to.
Using a multimeter to measure voltage
To begin, some multimeters are auto-ranging and others are manual. What this means is if you are measuring an AC (alternating current like the outlets in your house) you need to make sure your meter is set both on the right class of voltage as well as the proper range. This is why auto-ranging is almost a standard feature now.
One of my first meters, that A.W. Sperry one, you had to pick your voltage. So if you didn’t know what you were measuring, you started high, like 20,000 volts and moved down. Meters like the Fluke 115 just pick a range on their own. However, some Fluke meters do not go between AC and DC (direct current like a battery) automatically. The Fluke electrical testers usually do but not the meters.
Measuring voltage requires the electricity to be on in the device being measured.
Start by plugging the probes into the corresponding jacks on the multimeter. For some applications this is important, while for others, it does not matter. In the case of voltages, it matters sometimes. Helpful I know.
The black lead should be negative and the red test lead should go only to the volt/ohm/temp jack. If you’re measuring AC voltage, simply turn the dial to the “V” with a wavy line, like a tilde, over it (pic around somewhere.) That wave represents the alternating current, its sine wave.
Finally, touch the probes, also called leads or test leads, to the outlet, wire, device you are checking.
Checking DC voltage with a digital multimeter
To measure DC voltage, turn the dial to the “V” with a solid and a broken line over it showing direct current (no sine wave.) Side note: Tesla wanted the standard electrical system to be DC, Edison wanted AC. I don’t know if that is an urban myth or what. I do know that direct current can be more devastating than AC as far as your life is concerned.
Touch the negative test lead to ground and positive lead to what you’re checking in the circuit. The voltage reading should be displayed with a – symbol indicating voltage towards ground; a + symbol may or may not be displayed to indicate voltage moving away from ground.
Multimeters shouldn’t be so intimidating now. Meh, who am I kidding? They’re still a little bit scary, we are placing our hands a few inches away from deadly electricity to take readings and measurements. But now, you should be able to use a meter to measure voltages, both AC and DC.
There is also an electrical tester comparison chart here or a multimeter comparison chart here. If you learned something from this article, maybe you’d like to sign up? The sidebar has a sign-up section somewhere over there.
Thanks for reading. I really hope you learned something. Leave a comment. Got a tip? Share.