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How to measure resistance with a digital ohm meter

Learn how to measure an unknown resistor or potentiometer with a digital ohmmeter. This is a simple DIY article that will have you measuring resistance like a pro in minutes.


Depending on your digital multimeter, there will be a range of resistance settings. When measuring Ohms, set your meter on the highest setting first and work your way down until you get a precise measurement. For example, if your meter has ranges from 10 Ohms, 1,000 Ohms, 10,000 Ohms and 1,000,000 Ohms, set it to the 1M Ohms setting first.


First we will cover how to measure an unknown variable resistor, also known as a Potentiometer or POT for short.


Measuring a Potentiometer with a digital meter




First, use aligator clips and connect the meter leads to the two outside legs of the variable resistor. This will insure a secure connection with the legs of the resistor and free up your hands to handle the meter and turn the dial on the POT.


Measuring a variable resistor with a digital ohm meter




With the meter on the highest setting, you should now get a reading on the meter. You can dial the meter down to lower settings until you get a more precise measurement. If the meter is set too low, it will show an infinity reading, which means that the resistor is out of range of the meter setting. Depending on your particular meter, this is usually shown by a number 1.


The variable resistor shown above is reading 10.92 on the meter. The meter range is set to read in the thousands. This means that the POT shown has a maximum resistance of about 11K Ohms, or 11,000 Ohms. A resistor has a bit of tolerance from its rated capacity so this resistor was probably a 10K Ohm resistor from the factory.


Now you can set one of the aligator clip leads on the middle leg of the variable resistor. Leave the other lead on the outside leg of the variable resistor.


You can turn the dial on the Potentiometer to see how the resistance varies from near zero all the way to its maximum resistance.


Thats it.


How To Measure Standard Resistors


Now we can learn how to read the resistance of an unknown standard resistor.


The method for measuring the resistance of any standard resistor is the same as above. First, clip on some aligator clips to both ends of the resistor and to the meter leads for a solid connection.


Measure the resistance of a standard resistor


Your digital multimeter should immediately show a reading on its display. If not, then turn the selector dial to a higher setting and check your aligator clip connections.


The meter shown above is set to the 20,000 Ohms setting. The display shows 2.24 which means that this resistor is 2,2 K Ohms, or 2,200 Ohms.


As you can see, reading the value of an unknown resistor is very easy with a digital meter.

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Troy Reid



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