How to Test a Capacitor with a Multimeter [5 Easy Methods]

Are you trying to figure out how to test a capacitor with a multimeter in 2023?

As we know there are several ways to test a capacitor with the help of a multimeter. Follow this step-by-step guide to discover the tactics I used to diagnose the faulty capacitor.

A multimeter is a fantastic tool you may use to determine the capacitance by charging the known current. That measures the resulting voltage for capacitance calculation. Also, you can effortlessly get confirmation that the capacitor is damaged, faulty, or leaked.

With this in mind, we’ll explain how to check capacitor voltage with multimeter. Further, we’ll also guide how to check if a capacitor is bad without removing the component.

How to test a Capacitor with a Multimeter?

Use the multimeter and Connect the test leads to the capacitor terminals. Select the Capacitance setting on the multimeter and Read the measurement displayed. Please ensure that the capacitors from the circuit board are before starting testing. If the multimeter displays the capacitor’s value within the range it means that the capacitor is ok.

Here are a few different methods to test a capacitor. At the end of this article, we can get the answers to the below questions:

1. Using a Digital Multimeter With Capacitance Setting.
2. Using a Digital Multimeter Without Capacitance Setting.
3. Using an Analog Multimeter.
4. Testing a Capacitor With a Voltmeter.
5. Shorting the Capacitor Terminal.

This method is used to find the faulty capacitor by measuring the capacitance, Resistance, or potential difference across the capacitor. We will explain in detail how to measure capacitors to a Multimeter here.

If you want to learn how to test a capacitor with a multimeter, Follow this step-by-step guide to check and test for troubleshooting.

Warning: A capacitor may build up a dangerous residual charge. Before touching it or taking a measurement, Please ensure that you carefully discharge the capacitor by connecting a resistor across the leads. For Safe discharge, wear appropriate personal protective equipment recommended before any testing.

Using a Digital Multimeter With Capacitance Setting

Here’s my favorite and familiar way of testing a capacitor with the help of a digital multimeter. It is also a straightforward and accessible method of capacitor verification.

Testing capacitors with a digital In modern digital multimeter, you can find a capacitance meter and a voltage meter. Similarly, this method works on tiny SMD components as well. The following instructions demonstrate using your digital Multimeter to test an AC capacitor.

1. Remove the capacitor from the circuit and fully discharge it before measuring its value.
2. Turn the knob on your Multimeter to “capacitance” mode.
3. In Multimer, Farads’ capacitance value is displayed as the Farad is usually expressed in microfarads (F).
4. Connect the multimeter probe to the capacitor terminals. In polarization, connect the positive terminal to a red multimeter probe and the negative terminal to a black probe.
5. Write down the actual reading after checking the Multimeter on paper. 
6. The capacitor must be replaced if the printed and measured readings are significantly different or if both readings are zero.

It is this way that one can determine if a capacitor is bad. You can replace and troubleshoot your electronic device if the capacitor is faulty. It is a straightforward and standard method of testing a capacitor with a digital multimeter.

Using a Digital Multimeter With Resistance Setting

Several Digital Multimeters do not include a capacitance feature, so the above method is not applicable, but we can still test the capacitor by measuring its Resistance.

Step-by-step instructions on testing a capacitor with a multimeter by measuring its Resistance

1. Remove the capacitor from its circuit and make sure it is fully discharged.
2. Set the Multimeter knob to Ohm (unit of Resistance) or the Greek letter omega (*), as shown in Figure 1.
3. Connect the Multimeter leads to the capacitor terminals again, ensuring that the red one is on the positive and the black one is on the negative.
4. The first resistance reading that appears on display should be noted. Within a few seconds, it sets to display a value of infinity (Open).
5. Disconnect the probes and respect them repeatedly. It indicates that the capacitor is in good working order if the results are the same as before.
6. The capacitor is faulty (dead) if it doesn’t change in repeated tests.

How to test capacitor using an analog multimeter

By using other parameters, such as current (A), voltage (V), and Resistance (O), we can test the capacitor just like we can with digital multimeters. This section explains how to try the capacitor with a resistance measurement—this step-by-step guide on testing a capacitor with a simple analog multimeter.

• Follow the same steps again: remove the capacitor from its circuit and inspect it for complete discharge.
• Make sure your Multimeter is set to its resistance setting (Ohmmeter *) and select the higher range.
• The red probe should go on the positive terminal, while the black probe should be negative. 
• When the needle initially shows a low value and does not move further, it indicates a faulty capacitor.
• The needle pointer on the display of an analog multimeter measures the reading, and the position of the needle determines the capacitance result.
• It indicates that the capacitor is functioning correctly if the needle initially displays a low value and then moves to the right side and displays a higher value after some time.
• It is possible that the needle in the third case shows no resistance value or does not move for any value. That indicates that the capacitor is open and faulty.

How to test a capacitor with a digital multimeter

To check whether a capacitor is defective, we will use a simple voltmeter to measure its voltage rating. You can follow these steps to test a capacitor with a voltmeter in the following section: Testing a Capacitor With a Voltmeter.

• After a fully discharged capacitor, desolder it and remove it from the circuit. For measurement, you can also remove one lag.
• The capacitor’s voltage rating should be written on paper on the meter and checked outside the capacitor body. You can find the number after the capital “V” on any body part. For example, 16V,50V, or another value.
• The capacitor needs to be charged with a voltage less than its rating. If the capacitor’s rated voltage is 30 V, charge it with 9 V and 600 V at most minor.
• Ensure the positive terminal is connected to the red probe and the negative terminal to the black probe. 
• Connect the red probe to the positive terminal and the black probe to the negative terminal of your voltmeter. Now you’re ready to measure the voltage of the charged capacitor. 
• A capacitor that measures close to its rated value is suitable. The capacitor is faulty if the voltage gap is higher.

Traditional Method to Test Capacitors

This method was more popular in the old days, as it did not require any measuring devices for validation. This article will discuss how to test a capacitor without a multimeter.

While this method is risky and not recommended by professionals, safety precautions should be taken if necessary. Protective gloves should be worn, and metal surfaces should not be touched. Following is a step-by-step guide on shorting the capacitor terminal to test a capacitor. The following steps are involved in testing a capacitor. Again, the question is the same: How to try the capacitor without desoldering the component and possible.

• Remove the capacitor from the circuit board by desoldering, and the capacitor must be discharged completely. 
• For one to four seconds, connect red to the positive terminal and black to the negative terminal of the power supply.
• Short the capacitors to a metallic wire or rod as a safety precaution.
• A spark’s intensity can be used to determine the charging capacity of a capacitor. The capacitor is in good condition if the spark is strong and long. Otherwise, the capacitor is faulty.

How to test a capacitor with a multimeter in a circuit

Another question is testing the capacitor without desoldering or removing the capacitor from the circuit board.

When a capacitor is mounted On the circuit board, measuring the actual rated value through the multimeter or capacitance meter is impossible because several other components are placed on the same circuit board. Due to that capacitor gets an equivalent value rather than the actual.

The question is the same: How to test the capacitor without desoldering the component and possible.

Yes, it is possible to use an equivalent series resistance (ESR) meter or smart tweezers both work fine, but the ESR meter is more suitable for through-hole components, and smart tweezers for tiny SMD components. How to test capacitors without Desoldering Below 3 methods to identify the faulty capacitor.

1. Test a capacitor with an ESR Meter

The ESR meter device determines the equivalent series resistance without desoldering or removing it from the circuit board. This device can not measure the capacitance but can test the capacitor. You Can Buy It Online.

 Below are the steps that need to be followed to test capacitor insight into the circuit.

• To test the capacitor first and essential step is to discharge the capacitor completely. To discharge, you can short the capacitor terminal with the help of metallic items.
• Turn on the ESR meter and contact the red leg with the capacitor’s positive terminal and the black with the negative terminal. And short its leads till display zero reading.
• Note the reading of the ESR meter and note it down.
• Now compare the noted table reading on the body of the ESR meter. If the gap is within range, the capacitor is OK, and there is no need to change.
• ESR is not giving any table. You can check with a capacitor datasheet and compare it with the measured value.

2. Smart Tweezers

Smart Tweezers are more handy and Portable to do jobs more fun and comfortable. ESR Meter is not more reliable in dealing with the tiny SMD component.

However, the drawback of smart tweezers is that they are too costly. Otherwise, they work very smartly and effectively.

3. Visual inspection for Bad Capacitor

Sometimes, you can quickly check the capacitor by visual inception rather than smart tweezers or ESR meters.

A faulty capacitor gets swallowed on the top side and gets damaged or burnt remarks on the body. If you find such observations during inspection, replace the suspected capacitor with a fresh one.

FAQ:

Q. #1) What is a capacitor?

A capacitor is an electrical component that stores energy as an electric charge and is often found in electronic appliances like air conditioning fans and compressors to perform various functions. The component is a passive electronic device with two terminals.  

Further, these capacitors can be divided into two types: Electrolytes, associated mainly with vacuum and transistor power supplies, and Non-Electrolytics, compatible with direct current regulation. The capacitor is known initially and widely famous as a condenser. The effect of a capacitor is known as capacitance.

The capacitor is mainly made of two electrical conductor plates septated by a dielectric medium if we talk about practical capacitors. A potential difference between two conductor plates while connected across a battery results in positive and negative charges on terminals.

Q. #2) What are the safety precautions for testing capacitors?

Testing capacitors is a common task for electronic technicians. There are a few safety precautions that must be followed when testing capacitors. First, always use safety goggles when testing capacitors. Second, use a multimeter with the proper voltage range to test capacitors.

Third, make sure that the capacitor is connected correctly to the Multimeter. Fourth, do not exceed the maximum voltage rating of the capacitor. Finally, never use an excessive amount of force when testing capacitors.

Conclusion – Wrapping it up

Testing capacitors is an essential part of ensuring they are functioning correctly. There are a few different ways to test a capacitor, and each has advantages and disadvantages. One way to test a capacitor is to use a multimeter. This article describes how to test a capacitor using a multimeter.

With this information, you can answer how to test a capacitor with a multimeter in both conditions: without removing it from the circuit board and with it attached to the circuit board. Also, how to check capacitors without a multimeter.

You can identify faulty capacitors with digital multimeters, ESR meters, and intelligent tweezers. A multimeter is used to measure the ESR of a capacitor in a circuit, and smart tweezers are used for capacitor inspection.

Reference Sources

1. Books:
   • “Electrolytic Capacitors” by J.H. Evans
   • “Capacitors: Technology and Trends” by R.P. Deshpande
   • “Capacitor Handbook” by Cletus J. Kaiser
2. Online Articles and Tutorials:
   • Electronics Tutorials: Capacitors – Link
   • Electronics Notes: Capacitor Tutorial – Link
3. Educational Websites:
   • Khan Academy: Capacitors and capacitance – Link
   • HyperPhysics: Capacitors – Link
4. Manufacturer Resources:
5. Vishay Intertechnology – Capacitor Basics – Link
6. YouTube Channels:
   • Afrotechmods – Capacitors Explained – Link
7. Online Communities and Forums:
   • Electronics Stack Exchange: Link
   • Reddit’s r/AskElectronics: Link

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