Multi-meter are commonly used by electricians to test the voltage of circuits that require work and for troubleshooting circuits to locate the source of a problem.
Testing the circuit with a multi-meter prevents one from becoming subject to an electric shock, or allows one to pinpoint the exact source of trouble in an electric circuit.
However, electricians are not the only ones that are able to use a multimeter, there are multi-meters designed for residential use. The commercial multi-meters are available in digital Multimeter and analog forms and may easily be used by anyone.
The following sections explain how to use a multi-meter to test various characteristics of an electrical circuit. Multimeters area unit obtainable in a very big selection of options and costs.
DC Voltage Uses
DC Voltage is one amongst the foremost common uses of a multimeter. this is often used for any price from checking the voltage at an explicit a part of a circuit to the testing battery.
DC Voltage is displayed many other ways on multimeters however sometimes, either VDC or DCV is employed.
Selecting a scale – the dimensions that you simply choose can browse up to the expressed voltage (A scale of 20V would browse from -20V to 20V). Most multimeters provide you with a selection of scales that you’ll use. A mean multimeter could contain the subsequent scales 200m, 2000m, 20, two hundred and a thousand.
The dimensions that you simply select for your reading can have to be compelled to cowl the voltage varies that you simply are victimization, however, the lower scales can offer you with a better level of accuracy.
For example, if you were testing a one.5V AA battery you’d be the best victimization the 2000m scale. This scale can browse in mV (millivolts) this one.5V would be displayed as 1500. This scale can show a most of 2000 which might be 2V.
If however, you were testing a 9V PP3 battery you’d have to be compelled to use a better scale. The twenty scale which might browse up to 20V would be the dimensions to use.
Polarity – The polarity is not sometimes the best issue with DC Voltage as if you get the check leads the incorrect way around all that will happen is that the screen will show a minus image and also the voltage.
Resistance may be very helpful operate of a multimeter for excellent several reasons. we frequently use a multimeter on the resistance scale to see the worth of a resistance or as a straightforward technique for checking continuity (Some multimeters have a continuity function).
Selecting a scale – the size that you just choose for the resistance can have a control on the accuracy of your readings. The scales can scan from 0ohms to the worth of the size that you just have selected. you must aim to use a scale wherever the expected resistance is between the size below and therefore the value.
AC Voltage Scale
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I cannot emphasize however vital it’s to be terribly careful whereas doing this. Mains electricity will kill you, do not bit any of the metal components of you check leads whereas testing this. If your check leads or multimeter have any signs of harm, don’t USE THEM to check AC VOLTAGE.
Testing AC voltage is done in a very similar way to testing DC voltage. With AC polarity isn’t a problem because the polarity is dynamical fifty or sixty times per second relying upon wherever you’re within the world.
AC voltage is indicated on a multimeter by one in all the subsequent the letters AC, the letters ACV or a wavy line (Looks just like the letter S on its side). *The wavy line is real to represent an undulation.
Choosing the proper scale
With AC it’s terribly rare that you simply can have over 2 scales on your multimeter. Like all alternative settings on the multimeter price that you simply opt for is that the most value.
For the United Kingdom of Great Britain and Northern Ireland power tools that is between 220 and 240V, you’d desire a price over 250V. On the multimeter I even have before of Maine the dimensions would be 750V.
For United States power that is between one hundred ten and 120V, you’d desire a price over 130V. On the multimeter that I even have before of Maine that may be 200V.
Current are some things that you simply could from time to time got to live however it’s a little additional tedious than all of the opposite measurements that the multimeter takes because the multimeter must be serial with the instrumentation instead of in parallel.
To test current you’ll realize a group of crocodilian reptile clip leads helpful as you’ve got to interrupt into the circuit.
The majority of lower to middle very multimeters can solely check current on DC, however, higher finish ones could have AC current as a feature. Current is indicated on a multimeter with either the letter A or the letters DCA. If you can’t see either of those searches for the numbers with An or mA once them as they’ll be a current scale.
When measurement current it’s vital to recollect that the connections are going to be united. one in all the connectors can in all probability be united at the next rating than the opposite. If you’ve got a rough plan of the present that the device is going to be drawing you’ll be able to use the lower rating affiliation for higher accuracy. If you do not recognize the present rating it’d be suggested to begin off with the upper rated affiliation.
To use the upper rated affiliation swap your minimum into the connector and leave the plumbago blocked into the black connector.
Choosing the dimensions
The multimeter that I even have before of Maine uses a 10A fuse and therefore the lead is blocked into that socket. To use that scale I switch the dial on the multimeter to 10A within the DCA space.
If the reading is zero or below the explicit price of the lower fuse, in my case 200mA (0.2A) I might swap the minimum back and begin to scale back the dimensions till I got a helpful reading.
Frequency could be a feature that some multimeters wear them which might be quite handy once operating with timers, oscillators and radio circuits.
The frequency is going to be displayed in Hertz.
Frequency thusmetimes|is usually indicated on the multimeter by an sq. wave image but some multimeters embrace an sq. wave generator so it’s essential to ascertain the directions of your multimeter before victimization it.Audible Continuity/Diode.
Some multimeters have sounding continuity on them that is indicated by a series of curving lines to point an undulation. this can be a handy feature to own once testing tracks on circuit boards as if there’s a beep there’s an association if there’s no there’s no association.
This is typically combined with a diode tester which can permit you to figure out the polarity of a diode.