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How To Use A Multimeter To Test A Fuse

Updated on: July 10, 2019

The Introduction

This guide will certainly reveal you exactly how to utilize a digital multimeter (DMM), an essential tool that you can use to diagnose circuits, learn regarding other individuals’s digital layouts, and also to test a fuse. Thus the ‘multi’-‘meter’ or several measurement name.

The most basic things we measure are voltage as well as current. A multimeter is likewise excellent for some fundamental sanity checks and also troubleshooting. Is your circuit not working? Does the button job? Place a meter on it! The multimeter is your first protection when repairing a system. In this tutorial we will cover measuring voltage, current, resistance and continuity.

Every fixer ought to know their way around a multimeter, which has just north of a zillion makes use of for testing electronic components and circuits.

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

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

A multimeter is a measurement tool definitely needed in electronics. It integrates three essential features: a voltmeter, ohmeter, and also ammeter, and also in some situations continuity.

The tool permits you to recognize what is taking place in your circuits. Whenever something in your circuit isn’t working, it will certainly aid you repairing. Here’s some circumstances in electronics tasks that you’ll find the multimeter helpful:

  • is the switch on?
  • is this cord performing the electricity or is it broken?
  • just how much current is streaming via this led?
  • exactly how much power do you have left on your batteries?

What will multimeters measure?

Almost all multimeters can measure voltage, current, and also resistance.

A bunch of multimeters have a continuity check, causing a loud beep if 2 things are electrically linked. This is useful if, for example, you are building a circuit and also attaching cables or soldering; the beep suggests everything is connected and also nothing has actually come loose. You can also use it to make sure 2 points are not attached, to assist avoid brief circuits.

Some multimeters also have a diode check function. A diode resembles a one-way valve that only allows electrical power flow in one instructions. The specific feature of the diode check can differ from one type to another. If you’re collaborating with a diode and can’t tell which way it goes in the circuit, or if you’re unsure the diode is functioning effectively, the check attribute can be quite helpful. If your DMM has a diode check function, reviewed the manual to discover out specifically how it functions.

Advanced models could have various other functions, such as the capacity to measure as well as determine various other electric elements, like transistors or capacitors. Considering that not just about all multimeters have these functions, we will not cover them in this tutorial. You can read your multimeter’s guidebook if you need to use these features.

What Do All the Symbols Mean?

There’s a lot taking place when you take a look at the selection knob, yet if you’re only mosting likely to be doing some basic stuff, you will not also utilize fifty percent of all the setups. All the same, below’s a run-through of what each sign indicates:

Direct Current Voltage (DCV):Occasionally it will be denoted with a V– rather. This setting is used to measure straight current (DC) voltage in points like batteries.
Alternating Current Voltage (ACV): Sometimes it will be signified with a V ~ rather. This setting is utilized to measure the voltage from alternating current sources, which is practically anything that connects right into an electrical outlet, as well as the power coming from the electrical outlet itself.
Resistance (Ω): This measures just how much resistance there is in the circuit. The lower the number, the much easier it is for the current to flow with, and also the other way around.
Continuity: Usually denoted by a wave or diode symbol. This just examines whether or not a circuit is total by sending out a very tiny quantity of current with the circuit as well as seeing if it makes it out the other end. If not, then there’s something along the circuit that’s causing a problem– locate it!
Straight Current Amperage (DCA): Similar to DCV, yet rather of offering you a voltage analysis, it will certainly tell you the amperage.
Straight Current Gain (hFE): This setup is to check transistors and also their DC gain, but it’s mostly worthless, since most electrical contractors as well as hobbyists will certainly utilize the continuity check rather.

Your multimeter might likewise have a devoted setup for examining the amperage of AA, AAA, and 9V batteries. This setup is usually signified with the battery icon.

Once again, you probably will not even use fifty percent of the settings revealed, so don’t obtain overwhelmed if you only understand what a few of them do.

How to Use a Multimeter

For starters, let’s go over a few of the different parts of a multimeter. At the extremely basic level you have the tool itself, together with two probes, which are the black and red cords that have plugs on one end and steel ideas on the various other.

The tool itself has a display on top, which offers you your readout, as well as there’s a large selection knob that you can rotate around to choose a particular setting. Each setting might also have various number worths, which are there to measure different staminas of voltages, resistances, and also amps. So if you have your multimeter collection to 20 in the DCV area, it will measure voltages approximately 20 volts.

Your DMM will also come with 2 or 3 ports for connecting in the probes:

  • the COM port stands for “Common”, and also the black probe will constantly plug right into this port.
  • the VΩmA port (occasionally signified as mAVΩ) is just a phrase for voltage, resistance, and also current (in milliamps). This is where the red probe will certainly connect right into if you’re measuring voltage, resistance, continuity, and also current much less than 200mA.
  • the 10ADC port (occasionally represented as just 10A) is utilized whenever you’re measuring current that’s more than 200mA. If you’re uncertain of the current draw, begin with this port. On the various other hand, you would not use this port at all if you’re measuring anything various other than current.

Warning: Make certain that if you’re measuring anything with a current more than 200mA, you connect the red probe into the 10A port, as opposed to the 200mA port. Or else you could blow the fuse that’s within the multimeter. In addition, measuring anything over 10 amps could blow a fuse or damage the multimeter also.

Your measurement tool could have entirely separate ports for measuring amps, while the various other port is particularly simply for voltage, resistance, as well as continuity, however most less costly multimeters will certainly share ports.

Anyhow, let’s get going really using a multimeter. We’ll be measuring the voltage of a AA battery, the current draw of a wall clock, as well as the continuity of an easy cable as some instances to get you started and acquainted with utilizing a multimeter.

Components of a Multimeter

A multimeter is made up by four essential sections:

  • Display: this specific is where the measurements are presented
  • Selection Knob: this selects what you intend to measure
  • Ports: this is where you plug in the probes
  • Probes: a multimeter includes two probes. Generally, one is red as well as the various other is black.

Ports

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

COM

COM stands for usual as well as is virtually constantly connected to Ground or ‘-‘ of a circuit.The COM probe is traditionally black however there is no difference in between the red probe as well as black probe other than color.

10A

10A is the unique port used when measuring huge currents (higher than 200mA).

Selection Knob

The selection knob enables the user to set the tool to check out different points such as milliamps (mA) of current, voltage (V) as well as resistance (Ω).

Probes

2 probes are linked into two of the ports on the front of the device. The probes have a banana type adapter on the end that connects into the multimeter. Any probe with a banana plug will certainly work with this meter. This permits different kinds of probes to be made use of.

Probe Types

There are numerous various types of probes offered. Here are a few of our faves:

  • Banana to Alligator Clips: These are excellent cords for linking to big wires or pins on a breadboard. Great for executing longer term tests where you do not have to have to hold the probes in place while you control a circuit.
  • Banana to IC Hook: IC hooks work well on smaller ICs as well as legs of ICs.
  • Banana to Tweezers: Tweezers come in handy if you are needing to examine SMD parts.
  • Banana to Test Probes: If you ever before damage a probe, they are cheap to change!

Measuring Voltage

To start, let’s measure voltage on a AA battery: Plug the black probe right into COM as well as the red probe right into mAVΩ. Establish to “2V” in the DC (straight current) array. Nearly all mobile electronic devices utilize direct current), not alternating current. Attach the black probe to the battery’s ground or ‘-‘ and also the red probe to power or ‘+’. Press the probes with a little pressure versus the positive and adverse terminals of the AA battery. If you’ve got a fresh battery, you need to see around 1.5 V on the display (this battery is all new, so its voltage is a little more than 1.5 V).

You can measure DC voltage or AC voltage. The V with a straight line implies DC voltage. The V with the bumpy line implies AC voltage.

Measuring voltage

  1. Set the setting 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. See to it the red probe is linked to the port with a V beside it.
  3. Link the red probe to the positive side of your component, which is where the current is coming from.
  4. Connect the COM probe to the opposite side of your component.
  5. Check out the worth on the display screen.

Pointer: to measure voltage you need to attach your multimeter in parallel with the component you intend to measure the voltage. Putting the multimeter in parallel is placing each probe along the leads of the component you desire 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 know that you’ll have around 1.5 V. So, you must pick an array with the selection knob that can review the 1.5 V. So you need to pick 2V in the situation of this multimeter. If you get an autorange one, you don’t need to bother with the array you require to pick.

Begin by activating it, connecting the probes right into their respective ports and afterwards setting the selection knob to the highest number worth in the DCV section, which in my case is 500 volts. If you do not know at the very least the voltage variety of things you’re measuring, it’s constantly an excellent concept to begin with the greatest worth initially and afterwards work your means down until you obtain a precise reading.

In this situation, we understand the AA battery has a very reduced voltage, however we’ll begin at 200 volts just for the sake of example. Next, place the black probe on the adverse end of the battery as well as the red probe on the favorable end. Have a look at the reading on the display. Since we have the multimeter set to a high 200 volts, it reveals “1.6” on the screen, implying 1.6 volts.

Nonetheless, I want an even more exact reading, so I’ll move the selection knob reduced to 20 volts. Below, 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 establish the selection knob to a number value lower than the voltage of things you’re testing, the multimeter would certainly just read “1”, indicating that it’s strained. So if I were to establish the knob to 200 millivolts (0.2 volts), the 1.6 volts of the AA battery is too much for the multimeter to deal with at that setting.

Regardless, you could be asking why you would require to check the voltage of something to begin with. Well, in this case with the AA battery, we’re examining to see if it has any juice left. At 1.6 volts, that’s a fully-loaded battery. However, if it were to review 1.2 volts, it’s close to being unusable.
In an extra practical situation, you can do this sort of measuring on a car battery to see if it could be dying or if the generator (which is what bills the battery) is going poor. An analysis between 12.4-12.7 volts means that the battery remains in good condition. Anything lower which’s evidence of a dying battery. Furthermore, start your auto up as well as rev it up a little bit. If the voltage does not raise to about 14 volts or two, after that it’s likely that the alternator is having issues.

Overload

What occurs if you choose a voltage setting that is too reduced for the voltage you’re attempting to measure? Absolutely nothing negative. The meter will merely present a 1. This is the meter trying to inform you that it is overloaded or out-of-range. Whatever you’re trying to review is excessive for that particular setting. Attempt altering the multimeter handle to a the following highest possible setup.

Selection Knob

How come does the meter knob checked out 20V and not 10V? If you’re looking to measure a voltage much less than 20V, you resort to the 20V setup. This will certainly enable you to review from 2.00 to 19.99. The initial figure on numerous multimeters is only able to display a ‘1’ so the varieties are limited to 19.99 rather than 99.99. For this reason the 20V max array as opposed to 99V max array.

Measuring Resistance

Plug the red probe into the ideal port as well as turn the selection knob to the resistance area. Then, link the probes to the resistor leads. The means you link the leads does not matter, the result coincides.

Normal resistors have color codes on them. If you do not recognize what they imply, that’s ok! There are a lot of on-line calculators that are simple to make use of. Nonetheless, if you ever before discover yourself without web gain access to, a multimeter is very convenient at measuring resistance.

Pick a random resistor and set the multimeter to the 20kΩ setup. Then hold the probes against the resistor legs with the very same amount of pressure you when pressing a key on a key-board.

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

In this instance, the meter checks out 0.97, suggesting this resistor has a value of 970Ω, or regarding 1kΩ (remember you are in the 20kΩ or 20,000 Ohm setting so you need to relocate the decimal 3 areas to the right or 970 Ohms).

If the multimeter reviews 1 or shows OL, it’s strained. You will require to try a greater setting such as 200kΩ setting or 2MΩ (megaohm) setting. There is no harm if this take place, it just implies the variety knob requires to be readjusted.

Should the multimeter reads 0.00 or nearly no, then you need to reduce the mode to 2kΩ or 200Ω.

Bear in mind that lots of resistors have a 5% tolerance. This implies that the shade codes may suggest 10,000 Ohms (10kΩ), but due to the fact that of inconsistencies in the production procedure a 10kΩ resistor might be as reduced as 9.5 kΩ or as high as 10.5 kΩ. Do not fret, it’ll work simply fine as a pull-up or general resistor.

As a rule of thumb, it’s rare to see a resistor less than 1 Ohm. Keep in mind that measuring resistance is not excellent. Temperature can affect the reviewing a whole lot. Likewise, measuring resistance of a device while it is literally mounted in a circuit can be extremely difficult. The surrounding elements on a circuit board can greatly impact the reading.

The mockup typically resembles with a basic clock escaping of a AA battery. On the positive side, the cord going from the battery to the clock is separated. We merely position our 2 probes in between that break to finish the circuit again (with the red probe attached to the source of power), just this time our multimeter will certainly read out the amps that the clock is drawing, which in this situation is around 0.08 mA.

While a lot of multimeters can additionally measure rotating current (AC), it’s not truly an excellent idea (especially if its online power), given that AC can be harmful if you wind up slipping up. If you require to see whether an electrical outlet is working, make use of a non-contact tester instead.

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

SUGGESTION: to place the multimeter in collection, you require to position the red probe on the lead of a component as well as the black probe on the following component lead. The multimeter acts as if it was a cord in your circuit. If you disconnect the multimeter, your circuit will not work.

Prior to measuring the current, make sure that you’ve connected in the red probe in the ideal port, in this situation µAmA. In the instance below, the very same circuit of the previous instance is used. The multimeter belongs to the circuit.

Test Continuity

If there is very reduced resistance in between two points, which is much less than a couple of ohms, both factors are electrically connected as well as you’ll listen to a continuous sound. If the audio isn’t continual or if you don’t hear any kind of audio in any way, it indicates that what you’re testing has a damaged link or isn’t connected in all.

CAUTION: To be able to examine continuity you ought to shut off the system. Shut off the power source.

Touch both probes with each other and also, as they are attached, you’ll listen to a continual sound.To examination the continuity of a wire, you just require to link each probe to the cord tips.

Continuity is a terrific method to test if 2 SMD pins are touching. If your eyes can’t see it, the multimeter is normally a fantastic 2nd testing source. When a system is not working, continuity is another thing to help troubleshoot the system.

  • Establish your multimeter to the continuity setting utilizing the selection knob.
  • The readout on the screen will instantly read “1”, which means that there isn’t any continuity. This would be right because we have not attached the probes to anything yet.
  • Next, make certain the circuit is unplugged as well as has no power. After that attach one probe to one end of the cable and the other probe to the various other end– no matter which probe takes place which end. If there is a full circuit, your multimeter will either beep, reveal a “0”, or something other than a “1”. If it still shows a “1”, after that there’s a trouble as well as your circuit isn’t full.
  • You can also examine that the continuity attribute deals with your multimeter by touching both probes to each various other. This finishes the circuit and also your multimeter should let you know that.

A continuity test tells us whether two points are electrically linked: if something is continual, an electric current can stream freely from one end to the other.

If there’s no continuity, it indicates there is a break someplace in the circuit. This could indicate anything from a blown fuse or poor solder joint to an incorrectly wired circuit.

Changing the Fuse

One of one of the most common mistakes with a brand-new multimeter is to measure current on a bread board by penetrating from VCC to GND. This will right away short power to ground via the multimeter causing the bread board power supply to brownish out. As the current hurries via the multimeter, the inner fuse will certainly warm up and afterwards wear out as 200mA flows with it. It will certainly take place in a flash and without any type of actual distinct or physical indicator that something is incorrect.

Remember that measuring current is done in series (disturb 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 see that the meter checks out ‘0.00’ and that the system doesn’t switch on like it must when you affix the multimeter. This is because the internal fuse is broken and serves as a busted cable or open.

To change the fuse, locate your helpful dandy mini screw driver, and also start obtaining screws. The components and also PCB traces inside the multimeter are developed to take different quantities of current. You will certainly damage as well as potentially wreck your multimeter if you unintentionally press 5A with the 200mA port.

There are times where you need to measure high current tools like an electric motor or home heating component. Do you see the 2 areas to put the red probe on the front of the multimeter? 10A on the left and mAVΩ on the right? If you try to measure greater than 200mA on the mAVΩ port you run the danger of blowing the fuse. Yet if you use the 10A port to measure current, you run a much reduced threat of blowing the fuse. The trade-off is sensitivity. As we spoke about above, by making use of the 10A port as well as knob setting, you will just have the ability to check out down to 0.01 A or 10mA. Most of systems make use of more than 10mA so the 10A setting and also port works well sufficient. If you’re attempting to measure very reduced power (micro or nano amps) the 200mA port with the 2mA, 200uA, or 20uA can be what you need.

Conclusion

You’re now prepared to use your digital multimeter to begin measuring the globe around you. Do not hesitate to start utilizing it to answer many concerns. A digital multimeter will certainly address lots of concerns regarding electronics.

A multimeter is an important device in any electronics laboratory. In this overview, we’ve revealed you How To Use a Multimeter. You’ve discovered just how to measure voltage, current and also resistance, and exactly how to check continuity.