How To Use A Multimeter To Check An Outlet

Updated on: December 15, 2018



This tutorial will certainly reveal you exactly how to make use of a digital multimeter (DMM), an indispensable tool that you can use to diagnose circuits, find out about other people’s electronic styles, and even to check an outlet. Thus the ‘multi’-‘meter’ or several dimension name.

The most standard points we measure are voltage as well as current. A multimeter is also excellent for some standard peace of mind checks as well as troubleshooting. Is your circuit not functioning? Does the switch job? Place a meter on it! The multimeter is your very first protection when fixing a system. In this tutorial we will certainly cover measuring voltage, current, resistance as well as continuity.

Every fixer ought to know their means around a multimeter, which has just north of a zillion uses for screening digital parts and also circuits.

In this tutorial we’re going to reveal you just how to use a multimeter. This tutorial is primarily addressed for newbies who are starting in electronic devices and have no concept exactly how to utilize a multimeter and exactly how it can be useful. We’ll explore one of the most typical functions on a multimeter as well as exactly how to measure current, voltage, resistance and also just how to check continuity.

What is a multimeter and also why do you need one?

A multimeter is a measurement tool definitely needed in electronics. It incorporates 3 essential functions: a voltmeter, ohmeter, and also ammeter, as well as in many cases continuity.

The tool allows you to recognize what is taking place in your circuits. Whenever something in your circuit isn’t working, it will help you fixing. Right here’s some scenarios in electronic devices tasks that you’ll discover the multimeter helpful:

  • is the button activate?
  • is this cable carrying out the electricity or is it damaged?
  • just how much current is flowing with this led?
  • just how much power do you have left on your batteries?

What can multimeters measure?

Mostly all multimeters can measure voltage, current, and resistance.

A bunch of multimeters have a continuity check, causing a loud beep if two points are electrically attached. This is useful if, for example, you are building a circuit and also attaching cords or soldering; the beep suggests everything is linked and nothing has actually come loose. You can also utilize it to make certain 2 points are not attached, to aid protect against short circuits.

A handful of multimeters likewise have a diode check function. A diode is like a one-way shutoff that only lets electricity flow in one instructions. The precise function of the diode check can vary from one type to another. If you’re dealing with a diode and can’t tell which method it enters the circuit, or if you’re not exactly sure the diode is functioning properly, the check function can be fairly helpful. If your DMM has a diode check feature, read the guidebook to figure out precisely how it functions.

Advanced models may have various other features, such as the capacity to measure and identify other electric components, like transistors or capacitors. Since not all multimeters have these attributes, we will certainly not cover them in this tutorial. You can read your multimeter’s handbook if you need to make use of these features.

What Do Every One Of the Symbols Mean?

There’s a whole lot taking place when you consider the selection knob, however if you’re just going to be doing some fundamental stuff, you will not also make use of half of all the setups. In any type of situation, right here’s a run-through of what each sign implies:

Direct Current Voltage (DCV):quite often it will certainly be signified with a V– instead. This setup is used to measure straight current (DC) voltage in things like batteries.
Alternating Current Voltage (ACV): Sometimes it will certainly be signified with a V ~ rather. This setup is made use of to measure the voltage from alternating current resources, which is quite much anything that connects into an outlet, along with the power coming from the outlet itself.
Resistance (Ω): This gauges just how much resistance there remains in the circuit. The reduced the number, the much easier it is for the current to move through, and also the other way around.
Continuity: Usually denoted by a wave or diode icon. This just examines whether or not a circuit is total by sending a very small amount of current through the circuit and seeing if it makes it out the various other end. Otherwise, after that there’s something along the circuit that’s causing a trouble– discover it!
Direct Current Amperage (DCA): Similar to DCV, but rather than giving you a voltage reading, it will certainly inform you the amperage.
Straight Current Gain (hFE): This setup is to check transistors and also their DC gain, however it’s primarily pointless, given that the majority of electricians as well as enthusiasts will use the continuity check rather.

Your multimeter could also have a specialized setup for checking the amperage of AA, AAA, and also 9V batteries. This setting is generally signified with the battery icon.

Once more, you possibly won’t even use half of the setups shown, so do not obtain overwhelmed if you just know what a few of them do.

How to Use a Multimeter

For starters, allow’s discuss several of the various parts of a multimeter. At the very standard level you have the tool itself, together with 2 probes, which are the black as well as red wires that have plugs on one end and also metal ideas on the other.

The tool itself has a display on top, which gives you your readout, as well as there’s a large selection knob that you can rotate around to pick a details setting. Each setting may likewise have various number worths, which exist to measure various staminas of voltages, resistances, and also amps. So if you have your multimeter collection to 20 in the DCV section, it will certainly measure voltages as much as 20 volts.

Your DMM will additionally have two or 3 ports for connecting in the probes:

  • the COM port mean “Common”, and the black probe will certainly constantly connect into this port.
  • VΩmA port (occasionally denoted as mAVΩ) is merely an acronym for voltage, resistance, and also current (in milliamps). This is where the red probe will link into if you’re measuring voltage, resistance, continuity, and current less than 200mA.
  • the 10ADC port (sometimes represented as simply 10A) is used whenever you’re measuring current that’s greater than 200mA. If you’re unsure of the current draw, start with this port. On the other hand, you would not use this port in all if you’re measuring anything apart from current.

Caution: Make sure that if you’re measuring anything with a current greater than 200mA, you plug the red probe right into the 10A port, instead of the 200mA port. Or else you might blow the fuse that’s within the multimeters. Furthermore, measuring anything over 10 amps might blow a fuse or destroy the multimeter as well.

Your measurement tool may have totally separate ports for measuring amps, while the various other port is specifically just for voltage, resistance, and continuity, however a lot of cheaper multimeters will certainly share ports.

Anyway, allow’s get begun really making use of a multimeter. We’ll be measuring the voltage of a AA battery, the current draw of a wall clock, and the continuity of a straightforward cord as some instances to get you started as well as aware of using a multimeter.

Components of Multimeters

Multimeters are made up by 4 essential sections:

  • Display: this specific is where the dimensions are displayed
  • Selection Knob: this selects what you intend to measure
  • Ports: this is where you plug in the probes
  • Probes: a multimeter features 2 probes. Normally, one is red and also the other is black.


  • “COM” or “–” port is where the black probe ought to be linked. The COM probe is traditionally black.
  • 10A is made use of when measuring huge currents, higher than 200mA.
  • µAmA is utilized to measure current.
  • allows you to measure voltage and resistance as well as test continuity.


COM mean usual and also is usually linked to Ground or ‘-‘ of a circuit.The COM probe is traditionally black however there is no difference in between the red probe and black probe apart from shade.


10A is the special port utilized when measuring big currents (better than 200mA).

Selection Knob

The selection knob enables the individual to establish the tool to review different points such as milliamps (mA) of current, voltage (V) and resistance (Ω).


2 probes are connected into two of the ports on the front of the system. The probes have a banana kind port on completion that connects into the multimeter. Any kind of probe with a banana plug will collaborate with this meter. This permits different sorts of probes to be made use of.

Probe Types

There are several kinds of probes readily available. Below are a few of our favorites:

  • Banana to Alligator Clips: These are great cable televisions for attaching to big wires or pins on a breadboard. Great for doing longer term examinations where you do not need to have to hold the probes in area while you adjust a circuit.
  • Banana to IC Hook: IC hooks function well on smaller sized ICs and legs of ICs.
  • Banana to Tweezers: Tweezers come in handy if you are needing to examine SMD elements.
  • Banana to Test Probes: If you ever damage a probe, they are economical to change!

Measuring Voltage

To begin, allow’s measure voltage on a AA battery: Plug the black probe right into COM and the red probe right into mAVΩ. Establish to “2V” in the DC (straight current) variety. Nearly all mobile electronics utilize straight current), not alternating current. Connect the black probe to the battery’s ground or ‘-‘ and also the red probe to power or ‘+’. Squeeze the probes with a little pressure versus the positive and also adverse terminals of the AA battery. If you’ve got a fresh battery, you ought to see around 1.5 V on the display (this battery is brand brand-new, so its voltage is a little greater than 1.5 V).

You could measure DC voltage or AC voltage. The V with a straight line means DC voltage. The V with the wavy line means AC voltage.

Measuring voltage

  1. Set the mode to V with a wavy line if you’re measuring AC voltage or to the V with a straight line if you’re measuring DC voltage.
  2. Ensure the red probe is linked to the port with a V next to it.
  3. Connect the red probe to the silver lining of your component, which is where the current is originating from.
  4. Attach the COM probe to the various other side of your component.
  5. Review the value on the display.

Idea: to measure voltage you need to link your multimeter in parallel with the component you intend to measure the voltage. Positioning the multimeter in parallel is positioning each probe along the leads of the component you intend to measure the voltage.

Measuring a battery’s voltage

In this instance we’re going to measure the voltage of a 1.5 V battery. You understand that you’ll have around 1.5 V. So, you should pick an array with the selection knob that can review the 1.5 V. So you must pick 2V when it comes to this multimeter. If you obtain an autorange one, you don’t have to fret about the array you require to choose.

Start by activating it, connecting the probes into their respective ports and afterwards setting the selection knob to the greatest number value in the DCV area, which in my situation is 500 volts. If you don’t recognize at the very least the voltage series of the important things you’re measuring, it’s always a great concept to start with the highest worth first as well as then function your way down up until you get a precise reading.

In this case, we recognize the AA battery has a really low voltage, but we’ll start at 200 volts simply for the sake of example. Next, put the black probe on the unfavorable end of the battery as well as the red probe on the favorable end. Take an appearance at the analysis on the screen. Since we have the multimeter set to a high 200 volts, it reveals “1.6” on the display, indicating 1.6 volts.

Nonetheless, I desire a more precise analysis, so I’ll move the selection knob reduced to 20 volts. Right here, you can see that we have an even more exact reading that hovers in between 1.60 and also 1.61 volts. If you were to ever set the selection knob to a number value reduced than the voltage of the important things you’re testing, the multimeter would just read “1”, signifying that it’s overwhelmed. So if I were to establish the knob to 200 millivolts (0.2 volts), the 1.6 volts of the AA battery is also much for the multimeter to manage at that setup.

In any kind of situation, you could be asking why you would need to check the voltage of something to begin with. Well, in this situation with the AA battery, we’re inspecting to see if it has any type of juice left. At 1.6 volts, that’s a fully-loaded battery. However, if it were to check out 1.2 volts, it’s close to being pointless.
In a more practical scenario, you can do this kind of measuring on a car battery to see if it may be passing away or if the alternator (which is what bills the battery) is spoiling. An analysis in between 12.4-12.7 volts indicates that the battery remains in good condition. Anything lower which’s evidence of a passing away battery. Moreover, start your cars and truck up as well as rev it up a little bit. If the voltage does not boost to about 14 volts or two, after that it’s most likely that the generator is having concerns.


What takes place if you select a voltage setup that is as well low for the voltage you’re trying to measure? Absolutely nothing negative. The meter will just display a 1. This is the meter attempting to tell you that it is overloaded or out-of-range. Whatever you’re attempting to review is as well much for that certain setting. Attempt altering the multimeter handle to a the next highest possible setting.

Selection Knob

Why does the meter knob read 20V as well as not 10V? If you’re aiming to measure a voltage less than 20V, you count on the 20V setup. This will certainly permit you to check out from 2.00 to 19.99. The initial figure on several multimeters is just able to present a ‘1’ so the varieties are restricted to 19.99 rather of 99.99. For this reason the 20V max variety as opposed to 99V max range.

Measuring Resistance

Plug the red probe right into the best port and turn the selection knob to the resistance section. Then, attach the probes to the resistor leads. The method you connect the leads doesn’t matter, the outcome is the exact same.

Normal resistors have color codes on them. If you don’t understand what they imply, that’s ok! There are a lot of on the internet calculators that are simple to use. Nonetheless, if you ever before find yourself without net access, a multimeter is extremely convenient at measuring resistance.

Choose out an arbitrary resistor and also established the multimeter to the 20kΩ setup. Then hold the probes against the resistor legs with the very same quantity of pressure you when pressing a trick on a key-board.

The meter will certainly read one of three points, 0.00, 1, or the real resistor value.

In this situation, the meter checks out 0.97, implying this resistor has a worth of 970Ω, or about 1kΩ (remember you remain in the 20kΩ or 20,000 Ohm setting so you require to relocate the decimal three areas to the right or 970 Ohms).

If the multimeter reads 1 or shows OL, it’s strained. You will certainly require to try a greater setting such as 200kΩ mode or 2MΩ (megaohm) setting. There is no damage if this happen, it merely implies the variety knob needs to be adjusted.

Should the multimeter checks out 0.00 or almost no, then you need to decrease the mode to 2kΩ or 200Ω.

Bear in mind that several resistors have a 5% tolerance. This indicates that the shade codes may suggest 10,000 Ohms (10kΩ), but as a result of disparities in the manufacturing procedure a 10kΩ resistor can be as reduced as 9.5 kΩ or as high as 10.5 kΩ. Do not fret, it’ll function just fine as a pull-up or general resistor.

As a policy of thumb, it’s unusual to see a resistor much less than 1 Ohm. Bear in mind that measuring resistance is not ideal. Temperature can influence the reviewing a lot. Likewise, measuring resistance of a device while it is literally mounted in a circuit can be really challenging. The surrounding parts on a circuit board can substantially affect the analysis.

The mockup usually resembles with a standard clock escaping of a AA battery. On the favorable side, the cord going from the battery to the clock is broken up. We merely position our two probes in between that break to complete the circuit once more (with the red probe linked to the power resource), only this moment our multimeter will read out the amps that the clock is drawing, which in this instance is around 0.08 mA.

While a lot of multimeters can additionally measure alternating current (AC), it’s not actually a good concept (particularly if its live power), because AC can be harmful if you finish up slipping up. If you require to see whether an outlet is working, utilize a non-contact tester rather.

To measure current you need to keep in mind that elements in collection share a current. So, you require to link your multimeter in series with your circuit.

TIP: to place the multimeter in collection, you require to put the red probe on the lead of a component and also the black probe on the next component lead. The multimeter acts as if it was a cord in your circuit. If you detach the multimeter, your circuit won’t function.

Prior to measuring the current, make certain that you’ve connected at a loss probe in the appropriate port, in this situation µAmA. In the example listed below, the exact same circuit of the previous example is utilized. The multimeter belongs to the circuit.


If there is extremely low resistance in between 2 points, which is much less than a couple of ohms, the two points are electrically attached and also you’ll hear a continual audio. If the sound isn’t continual or if you don’t listen to any type of audio in all, it indicates that what you’re testing has a malfunctioning connection or isn’t connected in any way.

CAUTION: In order to check continuity you must turn off the system. Shut off the power source.

Touch both probes together and also, as they are connected, you’ll listen to a constant sound.To test the continuity of a cord, you simply need to connect each probe to the cable tips.

Continuity is a terrific means to check if two SMD pins are touching. If your eyes can not see it, the multimeter is normally an excellent 2nd testing resource. When a system is not working, continuity is another point to assist repair the system.

  • Establish your multimeter to the continuity setting making use of the selection knob.
  • The readout on the display will immediately check out “1”, which implies that there isn’t any kind of continuity. This would be appropriate since we haven’t connected the probes to anything yet.
  • Next off, make certain the circuit is unplugged as well as has no power. Then link one probe to one end of the wire and also the various other probe to the other end– it does not matter which probe takes place which end. If there is a full circuit, your multimeter will either beep, show a “0”, or something besides a “1”. If it still reveals a “1”, then there’s a trouble and your circuit isn’t total.
  • You can also evaluate that the continuity function functions on your multimeter by touching both probes per various other. This finishes the circuit and also your multimeter ought to let you know that.

A continuity examination tells us whether 2 points are electrically connected: if something is continuous, an electric current can flow freely from one end to the other.

If there’s no continuity, it indicates there is a break somewhere in the circuit. This might indicate anything from a blown fuse or negative solder joint to an improperly wired circuit.

Changing the Fuse

One of the most typical errors with a new multimeter is to measure current on a bread board by penetrating from VCC to GND. This will immediately brief power to ground via the multimeter causing the bread board power supply to brownish out. As the current rushes through the multimeter, the inner fuse will warm up and afterwards wear out as 200mA moves via it. It will occur in an instant and with no real distinct or physical sign that something is incorrect.

Bear in mind that measuring current is carried out in series (disrupt the VCC line to the breadboard or microcontroller to measure current). If you attempt to measure the current with a blown fuse, you’ll possibly observe that the meter reads ‘0.00’ which the system does not switch on like it needs to when you affix the multimeter. This is due to the fact that the inner fuse is damaged as well as serves as a damaged cord or open.

To change the fuse, locate your helpful dandy mini screw chauffeur, and also start getting screws. The elements and PCB traces inside the multimeter are developed to take different quantities of current. You will certainly harm and also potentially wreck your multimeter if you mistakenly push 5A via the 200mA port.

There are times where you need to measure high current devices like an electric motor or home heating element. Do you see both places to put the red probe on the front of the multimeter? 10A left wing and mAVΩ on the right? If you attempt to measure more than 200mA on the mAVΩ port you risk of blowing the fuse. However if you make use of the 10A port to measure current, you run a much lower threat of blowing the fuse. The compromise is level of sensitivity. As we discussed above, by utilizing the 10A port and knob setup, you will only be able to review down to 0.01 A or 10mA. Most of systems use greater than 10mA so the 10A setting as well as port functions all right. If you’re trying to measure extremely low power (mini or nano amps) the 200mA port with the 2mA, 200uA, or 20uA could be what you require.


You’re currently all set to utilize your digital multimeter to start measuring the world around you. Do not hesitate to begin utilizing it to respond to many questions. A digital multimeter will certainly address lots of questions regarding electronic devices.

A multimeter is an essential tool in any electronics lab. In this overview, we’ve revealed you How To Use a Multimeter. You’ve found out how to measure voltage, current and also resistance, and just how to examine continuity.