Continuity vs. resistance & how to test both with a multimeter

When your appliances start acting up, knowing how to use a multimeter can help you find the problem and repair it quickly. Two of the most common tests you’ll want to understand how to perform are continuity and resistance.

Whether it’s a faulty switch, a broken heating element, or something else, these simple tests can point you in the right direction and help you get your appliances back up and running. 

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What is continuity?

When an appliance part has continuity, it means that electricity can flow freely through that part or wire. It’s like an open path for electricity to travel through. 

Continuity is a smaller resistance measurement. You can test a switch for continuity to see if it’s making or breaking the electrical circuit as expected. Continuity testing can also test relay contacts to make sure they’re closing the circuit when energized. 

Breaks, shorts, or poor connections in wiring harnesses, electrical cables, and cords can also be tested this way, as continuity testing checks for an uninterrupted path for electrical current through a wire or cable.

What is resistance?

Resistance is measured in Ohms (Ω). It measures the amount of difficulty an electric current has when it travels along a wire or another conductor. Resistance testing is used to verify the actual resistance value of resistors matches the specified or labeled resistance. It can also identify if a resistor is open (infinite or OL) or shorted (0 resistance). 

A lot of resistance can be a sign that something isn’t working right. For example, if a heating element has too much resistance, it could mean it’s worn out.

Common parts that can be checked for resistance include heating elements in electric stoves, ovens and dryers as well as windings inside electric motors, wiring, printed circuit boards (PCBs), diodes and transistors.

How to test for continuity with a multimeter

Testing for continuity is one of the easiest things you can do with a multimeter. If you’re checking a part and you suspect it’s broken, continuity testing will give you a quick answer.

Here’s how to test for continuity:

1. Turn your multimeter’s dial to the continuity setting (usually represented by a sound wave or sideways WiFi symbol). You can also set the meter to the lowest resistance setting if your multimeter doesn’t have a dedicated continuity option.
2. Plug the black meter probe into the “COM” (common) port and the red probe into the port labeled with the ohm symbol (Ω).
3. Touch the two probes together. If your multimeter is set to continuity, it should beep. If you’re testing resistance, you’ll see a reading (typically close to 0 ohms).
4. Place one probe on each end of the part you’re testing. For instance, if you’re testing a wire, touch one probe to each end of the wire. If your multimeter beeps, you have continuity – meaning the wire or part is good. If it doesn’t beep (or shows infinite resistance), that means there’s a break in the circuit and the part needs to be replaced.

Read more: How To Use A Multimeter To Check Appliance Parts

How to test for resistance with a multimeter

Testing for resistance is especially helpful when checking parts such as heating elements, thermostats, or any other part that should have a certain resistance level.

Here’s how you can easily test for resistance:

1. Turn your multimeter dial to the resistance setting, which is indicated by the symbol Ω. 
2. Plug the black probe into the “COM” port and the red probe into the port marked with the ohm symbol (Ω).
3. Make sure the appliance is disconnected from the power source so that you’re only measuring the part’s resistance.
4. Place the meter probes on either end of the part you’re testing. For example, when testing a heating element, touch one probe to each terminal of the element.
5. Check the results. A low resistance reading (close to zero) typically means the part is good. A high resistance or an infinite reading (the multimeter will usually display “OL” or “∞”) usually means there’s a break in the circuit and the part is faulty.

Read more: Tool Maintenance 101: The Basics You Need To Know

FAQs

Find answers to the most common questions about multimeters and how to use them when testing for continuity and resistance.

What kind of multimeter should I get?

If you’re working with higher currents, a 20A multimeter and above would be more appropriate, but a 15-20A model is usually sufficient for most household testing. In most homes, the average circuit is rated for 15 to 20 amps, while electric clothes dryer circuits are usually 30 amps and ranges are 50 amps.

What should I do when using a multimeter?

• Make sure the multimeter is capable of testing the voltage you’re trying to check
• Avoid touching metal parts when testing
• Always make sure the multimeter is set correctly
• Never use the multimeter on live circuits without taking extra precautions to keep yourself safe

What should you do before using a multimeter?

• Check the settings to make sure it’s set correctly
• Test the meter on a known working device to make sure it’s functioning properly
• Make sure the multimeter is capable of testing the voltage you’re trying to check

What does OL mean on a multimeter?

OL means “overload” or that the measurement exceeds the maximum limit the multimeter can measure.

How do I know if my multimeter leads are bad?

If the multimeter gives inaccurate readings or no reading at all, then see if there are any frays or breaks in the rubber or plastic insulation at the ends of the leads.

Why is my multimeter not reading correctly?

If your multimeter isn’t reading correctly, it could be due to a dead battery, broken leads, or a wrong setting.

More information

Thanks for stopping by! If you have any appliance repair needs or projects, don’t hesitate to explore our other troubleshooting guides and repair videos. 

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