How to Test a Capacitor using Multimeter

The voltage storage devices like capacitors are found in different applications of circuits like compressors, heating, ac fan motor, etc. These are available in two types like electrolytic and non-electrolytic. Electrolytic type is used with the vacuum tube as well as power supplies of the transistor, whereas non-electrolytic type is used to control DC surges. Electrolytic type can be damaged due to fall short by discharging extra current. Non-electrolytic types are failed most frequently due to leakage of stored charge. There are different methods to test a capacitor so this article discusses an overview of a capacitor and how to test a capacitor.

What is a Capacitor?

Definition:  A Capacitor is one kind of electrical component, used to store energy in an electric charge form. These are used in different electrical and electronic circuits to perform different functions. The charging of a capacitor can be done by arranging a capacitor in an active circuit. Once it is connected, then the electric charge will start flowing through the capacitor. When the primary plate of the capacitor doesn’t hold the electric charge, then it is released back into the circuit throughout the secondary plate. So this process in the capacitor is known as charging & discharging.

How to Check a Capacitor?

There are different types of electrical and electronic components available in the market. Some of them are very sensitive to voltage spikes. Similarly, a capacitor is also sensitive to voltage swings so there is a chance of damage permanently. So to overcome this, a capacitor test plays an essential role to check the functionality of a capacitor.

How to Measure Capacitance?

A multimeter is used to determine capacitance through a charging capacitor with a known current to measure the resulting voltage and after that capacitance can be calculated. Here we have discussed how to test a capacitor with a multimeter.

For that, take a DMM (digital multimeter) to make sure the power supply of the circuit is OFF. For instance in an ac circuit, if the capacitor is used, then place the multimeter to calculate ac voltage. Similarly, if a capacitor is used in a dc circuit, then place the DMM to calculate dc voltage.

Check the capacitor once, if it leaks, cracks or damages then replace the capacitor. Set the dial to capacitance symbol which is known as capacitance measurement mode. The symbol frequently shares a mark over the dial through an additional function. Usually, to change the dial, a function button is pressed to turn on a measurement.

For an accurate measurement, the capacitor should be detached from the electrical circuit. Some multimeters provide a REL (Relative) mode. This mode is used to take away the test leads to capacitance whenever the values of low capacitance are measured. When a multimeter is used in a relative mode to calculate the capacitance, the test leads must be open & push the REL key. So that the test leads to a residual capacitance can be removed.

Fix the capacitor terminals to the test leads for a few seconds to let the multimeter to select the correct range. Examine the displayed measurement on the DMM. If the value of capacitance is in the range of measurement, then the multimeter will exhibit the value of the capacitor.

Some factors involved in the capacitance include the following.

• The lifespan of capacitors are less & they frequently cause malfunctions
• Capacitors can be damaged due to short circuit
• When a capacitor gets a short circuit, a fuse or other components used in the circuit may get damaged.
• When a capacitor opens, the components in the circuit cannot work properly.
• The value of capacitance can also be changed due to deterioration.

Capacitor Testing Methods

In most of the troubleshooting of electrical & electronics, there are a lot of troubles that can be occurred while testing a capacitor. Here, a capacitor can be checked through using an analog & digital multimeters. So that capacitor can be checked whether that is in good condition or damaged.

The capacitance value can be checked using a digital multimeter using a feature like capacitance measuring. Generally, to test a capacitor, there are different types of methods available like analog, digital, voltmeter, a multimeter with two modes like capacitance mode, ohmmeter mode, and traditional sparking method. These methods play an essential role while testing a capacitor to know whether the capacitor is good, open, bad, short, or dead.

Test a Capacitor using Analog Multimeter

To test a capacitor through AVO like ampere, voltage, ohmmeter, then follow the steps.

• Check the capacitor that is fully charged or discharged.
• Use ampere, voltage, ohm meter.
• Choose analog meter on Ohm and always choose a high range of ohms.
• Connect the two meter leads to the terminals of the capacitor
• The reading & evaluate through the following outcomes.
• The short capacitor will show extremely less resistance
• The open capacitor will not demonstrate any deflection over the Ohm meter display
• The good capacitor will illustrate low resistance after that slowly increases in the direction of the infinite. So, the capacitor is in an excellent state.

Test a Capacitor using Digital Multimeter

To test a capacitor through digital multimeter, then follow these steps.

• Check the capacitor is charge/discharge.
• Locate the digital multimeter on 1k.
• Connect the leads of this meter to the terminals of a capacitor.
• This meter will display some numbers, please note down.
• After that, it will come back to the Open Line. Every time it will show the same result so we can conclude that capacitor is in good condition.

Thus, this is all about an overview of how to test a capacitor. This method is mainly used for checking the functioning of a capacitor. We know that capacitor is used to store an electric charge. It includes two plates namely anode and cathode, where the anode includes positive voltage, and cathode includes negative voltage. The polarity of a capacitor can be checked by applying the positive voltage to the anode terminal of the capacitor. Similarly, the negative voltage can be applied to the cathode terminal of a capacitor. Here longer terminal of a capacitor is anode whereas the shorter terminal is known as the cathode.