Multiple Ways On How To Test A Capacitor With A Multimeter


This article consists of an overview on how to test a capacitor with a multimeter along with some critical frequently asked questions. We shall discuss the testing procedures in detail.

There are two methods in which we can perform the capacitor testing using the multimeter –

  1. Using an analog multimeter
  2. Using digital multimeter

The most sought-after technique of capacitor testing through a multimeter is to use the capacitance mode. Almost all improved multimeters have this feature. Here, we first need to discharge the capacitor and ensure that no charge is left in it. Then, we point the knob to the capacitance setting and attach the probes of the multimeter to the respective capacitor terminals. Now we check the readings displayed on the multimeter. If that match or come to a value near the readings mentioned in the capacitor’s body, then we can say that the capacitor is well-functioning.

How To Test A Capacitor With A Multimeter – using an analog multimeter

An analog multimeter is a testing device whose scope is limited to measuring a few electrical parameters like voltage, current, resistance, etc.

There is a resistance mode of the multimeter utilizing which we can test a capacitor. In this method, we take a simple AVO(Ampere, Volt, Ohm) meter to test the capacitor. Then we follow the below-mentioned steps-‌

  • ‌Check that the capacitor is entirely discharged.
  • ‌Move the multimeter knob and point to the resistance or Ohm mode. The resistance selected must be high.
  • ‌Join the capacitor terminals with the corresponding multimeter probes.
  • ‌If the reading comes out very low at first and then bit by bit increases to almost infinity, then it’s a suitable capacitor. Otherwise, the capacitor isn’t in proper working condition. It’s either open or short-circuited.

How To Test A Capacitor With A Multimeter – using a digital multimeter

There are mainly two ways to perform testing of a capacitor using a digital multimeter-

  1. The capacitance mode: In this operating mode, we first desolder the capacitor from the main circuitry and discharge it. Then we make the necessary connections using the multimeter probes and capacitor terminals. If the multimeter reads a value within the range given on the capacitor(with a tolerance of 5%), then it’s okay. If the value shown is very low, we can say the capacitor is dysfunctional.
  2. The resistance mode: This mode of operation is analogous to the analog resistance mode. Just for the digital multimeter, a suitable capacitor will display from zero to open line or infinity in a few seconds. If the reading constantly shows zero or a low value, the capacitor is dead.

FAQs

Why is it essential to discharge the capacitor before checking it through a multimeter?

Capacitors are one of the most crucial elements of any electronic circuitry. So they must be adequately examined before utilizing a device.

The first stage while testing a capacitor with a multimeter is to check whether the capacitor is entirely discharged or not. We know that the capacitors cannot release the entire amount of charge right after the power supply is turned off. The discharging process may take up to few seconds. If we connect the multimeter while the capacitor contains even a slight amount of charge in it, hazards may occur. Screwdrivers or bleed resistors are efficient in discharging the capacitors.

How do you check if a capacitor is bad with a multimeter?

We can use either the resistance or the capacitance mode of any multimeter to check the correctness of a capacitor.

In the resistance mode, the high ohm range must be set. After we establish a connection between the probes and the capacitor terminals, we need to look for the movement of the meter. If the meter doesn’t slowly move towards infinity starting from zero, then the capacitor is bad. In the capacitance mode, the DC voltage should be set high. The multimeter gives a reading when we join the probes to the capacitor terminals. If the reading comes out of the mentioned range of the capacitor, then we can say that the given capacitor isn’t good.

Can you test a capacitor without removing it?

An ESR meter is effective when we want to check a capacitor without having it desoldered, i.e., in a circuit.

ESR stands for equivalent series resistance. An ESR meter puts the capacitor on test by passing an AC current of 100 kHz frequency through it. Therefore some voltage is produced, and the meter displays the value. If this value is equivalent to the value mentioned in the ESR meter, then the capacitor is in good condition.

Can you check continuity through a capacitor?

Continuity check is defined as the process of checking current flow in electrical circuitry.

The first stage of continuity check is to remove the capacitor from the circuit and discharging it completely. Then, we rotate the multimeter knob and point it to continuity test mode. We connect the capacitor terminals to respective multimeter probes. If we observe a continuous sound or LED light followed by a pause and then an open line on the screen, then the capacitor can be called good. Otherwise, the capacitor is faulty.

What is the capacitor symbol on a multimeter?

The capacitor symbol [-|(-] in a multimeter symbolizes the capacitance.

When a capacitor is subjected to a current, it begins to charge. So voltage develops, and with the help of the voltage, the multimeter determines the capacitance.

Will a multimeter discharge a capacitor?

A multimeter is originally combined testing equipment that determines voltage, current, capacitance, resistance, and some other adjacent measurements of any electrical device. So, it cannot directly discharge a capacitor.

However, we can find out the voltage present in the capacitor. For that, the DC voltage must be set to peak. Now we properly hold the probes with capacitor terminals and get the voltage displayed on the multimeter screen. If the voltage value shows less than 10 volts, then we can say that the capacitor is entirely discharged. If the value is more, we can refer to different discharging methods depending upon the amount.

How do you test a start capacitor?

A start capacitor is typically a motor capacitor that pushes the motor to initiate turning.

To test a start capacitor, we perform the following steps-

  • We point the knob to capacitance mode.
  • ‌Then any of the multimeter probes are held with the negative terminal of the capacitor, and the other probe is attached with the positive terminal firmly. The multimeter screen will now display a value.
  • ‌Now we exchange the probes and again connect to the terminals. A new value is displayed. We need to repeat this process almost five to six times and note down the values.
  • ‌If all the readings fall between the range printed on the body of the capacitor, then the capacitor is good.

What is the capacitance setting on a multimeter?

The capacitance or capacitor setting on a multimeter is a specific feature that primarily measures the capacitance.

The capacitance mode helps the user to check if the capacitor is in good condition or not. In the capacitor mode, the knob points to the “C” marked in the multimeter. We can find the value of capacitance by correctly attaching the probes to the capacitor terminals.

What setting do you use to test a capacitor?

There are different settings to test a capacitor through a digital or an analog multimeter.

The most common practice is to have the multimeter knob at the capacitance setting while testing a capacitor.

How do you check a capacitor without a multimeter?

Traditionally, experienced engineers and technicians use another method of capacitor testing that doesn’t involve multimeters.

This method is significantly risky and is performed with extreme precautions. Here, the capacitor is taken out from the circuit board initially and discharged. Next, the capacitor leads are connected to 240 V DC or 230 V AC supply voltage. The power supply is turned on, and the capacitor is charged for 2-3 seconds. Now the capacitor terminals are short-circuited. If this yields a large and bright electrical spark, the capacitor is well. If the spark is negligible, the capacitor is not fine.

Kaushikee Banerjee

I am an electronics enthusiast and currently devoted towards the field of Electronics and Communications . My interest lies in exploring the cutting edge technologies. I'm an enthusiastic learner and I tinker around with open-source electronics. LinkedIn ID- https://www.linkedin.com/in/kaushikee-banerjee-538321175

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