How to Use a Multimeter?

A multimeter is a device that measures electric currents, voltage, and resistance. 

Most electricians use this tool daily to diagnose electrical problems and help them find the problem in wiring systems if they have no idea where it might be. 

An electrician needs to know how to use it properly to read accurate measurements from their meter readings.

An electrician’s most important tool in their multimeter. It allows them to test the voltage of an electrical circuit, measure current flow in a wire and check for continuity. But how do you use one?

The first thing you need to do is make sure your multimeter is set up correctly; it should be on the AC Volts-DC Volts-Ohms scale, with a range between 100V and 600V AC or DC. 

Next, if your meter has different ranges (e.g., 200V – 400V), choose the appropriate range before making any measurements. 

The last step is to test the object being tested by touching two probes together at either end of whatever you are testing; this will help eliminate false readings.

Multimeter Basics and its Functions

A multimeter is a piece of standalone test equipment that can measure voltage, amperage, and ohms. It also measures capacitance, frequency, and transistors’ gain if you want to get fancy. 

They were invented back in the 1920s when they provided such high accuracy levels for measuring quantities in micro or nano ranges which was an expensive affair at the time by today’s standards these meters are often digital because it offers decimals as opposed to analog where precision measurements must be done with switches on their front panel.

Digital Multimeters Types

Knowing the difference between manual and auto-range DMMs can be a huge boon to your work. 

Auto range means that you don’t have to do any calculations, but if an amateur misuses it, then its circuitry may blow up in as little time as two seconds! 

Manual DMM’s on the other hand, offer increased safety from careless errors because they require some basic math for operation – no worries about blowing anything up here. 

The price of these types of meters also varies significantly, so make sure to consider this when making your purchase decision.

Reading Temperatures Using Multimeter

Multimeters are an indispensable tool for any electrician. Besides their excellent electrical testing capabilities, most modern multimeters can also take temperature readings. 

Rotate the meter’s dial to the temperature mode, then press the select button and toggle between Fahrenheit and Celsius with a quick push of your thumb on its faceplate screen! 

With this handy device, you no longer need to touch appliances when they’re hot or cold – plug in a thermocouple into it or insert a probe if making way too many trips from one device to another is getting old fast.

Testing Extension Cord With a Multimeter

There are a lot of hazards that come with using old extension cords. If you don’t test them periodically, the cord may short circuit and shock you or light your house on fire! 

To avoid this tragic fate, unplug the cord from its socket before turning it into an electric hazard by plugging in your ohmmeter to measure resistance.

To test the cord’s ground, push the red probe into the small hole on the cable’s female end. Then touch the black probe to one of two protruding prongs (the other should be touching soil). 

A continuous circuit measured from these two ends will have a less than 8 ohms resistance and most likely under 1 ohm for optimal measurement. 

Now, make sure there is no contact between the wire connecting the ground pin with either of the remaining wires in this configuration by testing it again using only one probe at a time- if you measure open circuits, then your string theory checks out!

Next, insert the red probe into one of the shorter slots on its end. Touch it with your black counterpart and see if you have any continuity through the cord at all by touching each side in turn.

First, touch where there is a broad flat prong or round plug to determine what type of socket this cable belongs to – electrician talk for “how big” they are (round plugs are usually higher wattage). 

Then take notice which slot has less resistance: short or long? Once that’s done, use whichever probe goes best to sense electrical contact from both ends simultaneously because that way, you can test for voltage when using extension cords.

If the cord doesn’t have any shorts, run a voltage test. Unplug it from an electrical outlet and rotate your meter’s dial to Volts AC; push one probe into the female end of the cable while inserting another in its slot. You should see close to 120 volts on your meter screen!

Now move the red probe into the longer (neutral) slot to confirm a reading of about .1 millivolts. Pick up your black probe and insert it in one of two slots on either end for voltage readings that will let you know if this extension cord is safe or not!

Testing Electrical Outlets Using Multimeter

To determine if the wall outlets in your home deliver the correct voltage, plug a black probe into one of its black COM ports and red probes into the Volts port. 

Turn on this rotary switch labeled “Vac” or indicated by a wavy line with an arrow pointing down from left to right; this will change it over so that you can measure AC volts (120 volts), which is what modern homes usually have now.

Push the red probe’s tip into the shorter (hot) of the two vertical slots on your outlet. Insert the black probe into the more extended slot (neutral). Check for a readout on the meter’s screen; it should be between 110-120 volts. 

Next, remove black probes from the outlet and insert one in the small rounded hole below outlets (+ ground); if you get a different reading, call an electrician. That means your wiring is potentially malfunctioning or not appropriately grounded!

Choosing Multimeter

The best multimeter for you will depend on what you intend to do if you’re a beginner or professional electrician and your budget. Professional-level meters are more expensive, but they offer much better accuracy and durability than basic models at around $35-$200+. 

You can also find hybrid versions that combine the features of both types, so it is essential not only to know how many measurements each meter offers but whether one type in particular suits your needs: voltage alone vs. current/resistance; digital readout vs. analog dials.

Basic meters measure the three most straightforward values–voltage, current (amperage), resistance–and cost about $5. However, these aren’t good options because they’re just too inaccurate and delicate.

About Blake Sutton

Blake has worked as an electrician for over 10 years, receiving his Journeyman Electrician license in 1998. Looking to take his professional electrical career further, in 2008 he received his Bachelor of Science in Electrical Engineering (BSEE) from the University of Texas in Austin. Blake now works full time as an electrical engineer, specializing in power systems.