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How to Test a Capacitor? 4 Ways to Check a Capacitor

How to Test & Check a Capacitor with Digital Multimeter and Analog AVO Meter.

By Four (4) Methods with pictorial Views.

In Most Electrical and Electronics troubleshooting and repairing, we face this trouble that how to test and check a capacitor? Is it Good, Bad (dead) Short or Open?

Here, we can check a capacitor with Analog (AVO Meter i.e. Ampere, Voltage, Ohm meter) as well as Digital multimeter.

Note: To find the Value of Capacitance, you need a Digital meter with Capacitance measuring features.How to Test a Capacitor with Digital Multimeter and Analog AVO Meter. By Four (4) Methods with pictorial View.

 Below are four (4) methods to check & test that a Capacitor is Good, Bad, Open, Dead, or Short.

Also Read:

Method 1.

Traditional Method to test & check a capacitor (Not Recommended for everyone but professionals only)

Note: This method is dangerous, please be careful to do this practice. Make sure that you are a professional Electrical Engineer and there are no other option to check the capacitor because serious damages may occurred during this practice). now go ahead.

Suppose you want to check the Capacitor (for example, Fan Capacitors, Room Air Cooler Capacitors etc.)

Warning & Recommendations for testing a capacitor by method 1.

For better safety, use 24V DC instead of 230V AC. in case of absence of the desired DC 24V system, you can use 220-224V AC, but you have to make a serial of resistors (say 1kΩ~10kΩ, 5~50Watts) to connect between capacitor and 230V AC supply.So that, i will reduce the charging and discharging current.

  1. Disconnect the suspected capacitor from the power supply or make sure at least one lead of the capacitor is disconnected.
  2. Make sure it is fully discharge.
  3. Connect leads to the Capacitors terminal.
  4. Now connect safely these leads to 230 V AC Supply for a very short period (about 1-4 Sec) [or for a short time where the Voltage rise to 63.2% of the Source Voltage] .
  5. Remove Safety leads from the 230 V AC Supply.
  6. Now Short the Capacitor Terminal (Please Be Careful to do that).
  7. If it makes a strong spark, then the capacitor is good.
  8. If it makes a weak spark, then it is a bad capacitor and change it immediately.
How to Check a Capacitor with Digital Multimeter and Analog AVO Meter. Four Methods (pictorial) ViewMethod 2.

Check & Test a Capacitor By Analog Multimeter ( AVO = Ampere, voltage, Ohm Meter )

  1. Make sure the suspected capacitor is fully discharged.
  2. Take an AVO meter.
  3. Select analog meter on OHM (Always, select the higher range of Ohms).
  4. Connect the Meter leads to the Capacitor terminals.
  5. Note The reading and Compare with the following results.
  6. Short Capacitors: Shorted Capacitor will show very low Resistance.
  7. Open Capacitors: An Open Capacitor will not show any movement (Deflection) on OHM meter Screen.
  8. Good Capacitors: Initially, it will show low resistance, and then gradually increases toward the infinite. It means that Capacitor is in Good Condition.
how to check that is a capacitor is good, open, dead, or short?
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Method 3.

Test & Check a Capacitor By a Digital Multimeter

  1. Make sure the capacitor is discharged.
  2. Set the meter on Ohm range (Set it at lease 1000Ohm = 1k).
  3. Connect the Meter leads to the Capacitor terminals.
  4. Digital meter will show some numbers for a second. Note the reading.
  5. And then immediately it will return to the OL (Open Line). Every attempt of Step 2 will show the same result as was in step 4 and Step 5. It’s mean that Capacitor is in Good Condition.
  6. If there is no Change, then Capacitor is dead.
How to Check a Capacitor with Digital Multimeter and Analog AVO Meter. Four Methods

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Method 4.

Checking Capacitor By Multimeter in the capacitance Mode

Note: You can do this test with a multimeter if you have a Capacitance meter on your multimeter. Also, this method is good for tiny capacitors.

  1. Make sure the capacitor is fully discharged.
  2. Remove the capacitors from board or circuit.
  3. Now Select “Capacitance” on your multimeter.
  4. Now connect the capacitor terminal to the multimeter leads.
  5. If the reading is near to the actual value of the capacitor (i.e. the printed value on the Capacitor container box).
  6. Then the capacitor is in good condition. (Note that the reading may be less than the actual value of the capacitor (the printed value on the Capacitor container box).
  7. If you read a significantly lower capacitance or none at all, then capacitor is dead and you should change it.
how to check a capaccitor that is good, bad, open, dead or short?You might Also read:

By: Engr Wasim Khan.

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20 comments

  1. EXCELLENT TUTORIAL

  2. Thank you. This is very useful information.

  3. just found this article that gives a far safer and good way to perform basic test on a capacitor forum.allaboutcircuits.com/showthread.php?t=5326<br the current article is very lacking in warnings and contains dangerous advice, I am an electronics engineer and as I said in my previous comment a professional would NEVER place a suspect cap across the mains like that

  4. A professional would NEVER try option 1, if this was April 1st I could see this being published, <br />Capacitors DONOT store AC volts, to wack mains across an arbitrary capacitor is going to get someone KILLED, this option should be removed ASAP<br /><br />the whole theory is wrong…<br /><br />a capacitor rated at 250V AC does not mean it will store AC and capacitors are not rated for power

  5. I agree that method 1 is very dangerous.

  6. nice it is very use ful parameters

  7. nice it is very use ful parameters
    and i see it done by electician to check the capacitor

  8. Wow that was good to know! This tutorial show how to use a digital multimeter (DMM), an indispensable tool that can use to diagnose circuits. The most basic things we measure are voltage and current. A multimeter is also great for some basic sanity checks and troubleshooting. Now this tester is also available which makes electrical testing easier with a wide range of multifunction testing accessories and ancillaries.Thanks

  9. Thanks. Sir
    It’s the science of alms

  10. I agree. Connecting a suspect capacitor across mains is very dangerous. Capacitors used in
    AC circuits are generally for delaying the AC cycles to mimic another phase. This second phase helps in turning AC motors. It also supplies a current boost to get the motor turning.

  11. very good educational,thank a lot

  12. Thank you on the capacitor info.

  13. Samuel Ngobeni

    I truly find the information about the capacitor very useful. Thanks

  14. how can use DMM to measure variable capacitor. thanks

  15. Thank you very much for this perfect training

  16. archana tyagi

    how to measure capictance for 1 hp motor or 70 watt fan, any formula? please help..

  17. None of these methods will determine if a capacitor is good, although some of them will show you if a capacitor is bad. A capacitor has to be tested at it’s rated voltage and the current draw must meet the specs at the rated voltage.

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