How to Test a Capacitor with a Multimeter

In this multimeter use guide, learn how to measure capacitance of a capacitor within a circuit using a multimeter. Understand what capacitance measurement and capacitors are, the importance of maintaining capacitors, units of capacitance, and how to use a multimeter to measure a capacitor’s capacitance.

This article provides a step by step guide on how to test a capacitor with a multimeter.

Introduction to Capacitor Testing

Capacitor testing separates the pros from the amateurs in electronic circuit maintenance. You know that capacitors—electrolytic, ceramic disk, or tantalum—store and release electrical energy that keeps circuits running. A bad capacitor kills circuits fast and creates headaches you don't need. Your digital multimeter measures capacitance and spots trouble before it spreads. Master capacitor testing and you control your circuits. You prevent breakdowns. You extend component life. You work smarter, not harder. This guide teaches you to measure capacitance like a pro, recognize failing capacitor symptoms, and troubleshoot problems with your multimeter that actually get results.

Preparing for Capacitor Testing

Preparation wins every time. Grab a reliable digital multimeter—your go-to tool for measuring capacitance, dc voltage, and ac voltage across any capacitor type you'll encounter. Master the capacitance measurement mode on your meter. This setting delivers accurate readings every single time. Handle electrolytic capacitors, ceramic disk capacitors, and tantalum capacitors with precision. These components demand respect—they're sensitive to voltage and current flow.

Safety isn't optional—it's mandatory. Discharge that capacitor before you test. Use a known resistor to safely release stored charge. This step protects your multimeter and saves your circuit components from damage. Working with polarized capacitors like electrolytics and tantalums? Identify those positive and negative terminals first. Connect your meter leads correctly. Run a visual inspection. Spot signs of short circuits, swelling, or leakage? You've found your faulty capacitors.

Follow these preparation steps and you'll measure capacitance like a pro. Choose the right tool. Know your multimeter's functions. Discharge safely. Inspect for damage. You'll keep your circuits running smoothly and get results that matter.

Discharging the Capacitor Before Testing

Discharge your capacitor before you test it. Period. Electrolytic capacitors and power supply capacitors store dangerous electrical charge long after you shut down the circuit. That stored energy will shock you and fry your digital multimeter. Smart technicians discharge first, test second.

Grab a 20,000 Ω resistor rated at 5 watts—this handles most jobs perfectly. Connect it across the capacitor terminals for a few seconds. The stored voltage bleeds off safely, protecting your capacitor and every other component in the circuit. Skip the insulated screwdriver trick. Shorting terminals creates sparks, damages capacitors, and wrecks circuits. You're better than that.

Gear up with insulated gloves and safety glasses when you work with high voltage or large capacitors. After discharge, verify the capacitor is safe with your multimeter. Check the voltage across the terminals—you want zero volts. No shortcuts. Only a fully discharged capacitor gives you accurate capacitance readings.

Larger capacitors and high voltage units take more time to discharge completely. Use a specialized discharge tool for these bigger jobs. Follow the manufacturer's procedure. Professional work demands professional methods.

Discharge first, test second—this protects you, your meter, and your circuit's integrity. You get accurate capacitance values and keep your troubleshooting safe and effective. No surprises, no accidents, just the reliable results that separate pros from amateurs.

Follow Along on SkillCat: "Using a Multimeter" Course!

Want to test your knowledge? Skip to the quiz!

Multimeter Basics

There are two types of multimeters: digital multimeters and clamp multimeters. Most of what is pictured in this guide is a digital multimeter. Most digital multimeters have a capacitance mode, which is the standard and most straightforward method for testing capacitors. When testing a capacitor, the multimeter should be set to capacitance mode. This is often indicated by a specific symbol on the multimeter set. 

• Multimeters can be used to measure various electrical measurements:

  • Measure voltage in Volts

  • Measure current in Amperes

  • Measure resistance in Ohms

  • Measure continuity in Ohms

  • You can also perform a continuity test on a capacitor by setting the multimeter to continuity mode and touching the probes to the capacitor terminals. If the multimeter emits a continuous beep during this test, it indicates a short circuit within the capacitor. 

  • Measure capacitance in Farads - this is the focus of this guide!

  • Measure temperature in Farenheit or Celcius

• Multimeters have 2-4 ports for the provided test leads to be plugged into.

  • Test leads have one end of the wire called the plug end that plugs into the multimeter port. The other end of the wire called the probe end is used to touch the component of measurement. 

  • When plugging in the meter leads, the red probe is used for the positive terminal and the black probe for the negative terminal of the capacitor. Proper probe placement and polarity are important for accurate measurement.

  • Capacitors have physical leads, known as capacitor leads, which must be properly identified and connected to the correct probes during testing.

  • Remember that black lead represents the negative probe, and red lead represents the positive probe.

  • Ensure that the probe ends of your test leads do not touch as you measure using the multimeter, as that can short the circuit and become a safety hazard.

  • Instead of test leads, alligator clips can also be used.

Smart tweezers are a specialized tool for testing small or surface mount capacitors, providing precise measurement and easy handling.

Before using your multimeter, always check it for signs of damage to ensure safety.

When using a digital multimeter, set it to the correct mode and range for capacitance measurement. For advanced testing, an ESR meter can be used to check the health of capacitors, especially while they are still in-circuit, by measuring their equivalent series resistance.

Before electrical testing, perform a visual inspection of capacitors for signs of damage such as bulging or leaking. Visual inspection can reveal if a capacitor may need replacement.

Why Should You Measure Capacitance?

Capacitance is the ability of an electronic component - often a capacitor - to store an electrical charge. Capacitance measurement refers to the "capacity" of charge a capacitor holds. The unit of measurement for a capacitor is farads, with more accurate readings using microfarads.

Capacitors are electronic components that store electrical energy or charge without producing it. Capacitors provide bursts of power when needed and stabilize voltage by absorbing and releasing charge quickly. They are essential in power supplies, radio transmitters, and flash photography, providing necessary energy discharges. There are many types of capacitors for different circuits and purposes - for example, electrolytic capacitors are used in filtering devices whereas film capacitors are used for energy discharge applications. For instance, a particular capacitor such as a ceramic capacitor is often used for high-frequency bypassing in audio circuits due to its low inductance and stability. 

Malfunctioning or faulty capacitors is a common cause to failed circuits due to having limited life. Checking capacitance measurements consistently helps to tell if your capacitor is still working effectively or if it short circuited. The measured capacitance should be compared to the expected value specified by the manufacturer for that particular capacitor to determine if it is functioning properly. If your capacitor short circuits, it means that the fuse has been blown and cannot be used; surrounding electronic components may also be effected. A short circuit in a capacitor can damage other components and disrupt the operation of circuit components, highlighting the importance of testing capacitors to protect the entire circuit. High ESR in a capacitor can also reduce circuit efficiency and reliability, especially in power supply and audio applications.

Digital multimeters are the most common tool used to measure capacitance and many other electrical measurements. A capacitance meter is also used to measure capacitance. A capacitance meter may used in more special cases, as digital multimeters can only measure capacitance under a constant DC voltage signal. A healthy capacitor should be within ±10-20% of its rated value.

Understanding Capacitor Types

Capacitors aren’t just components—they’re the backbone of every electronic circuit you’ll work on. Master the four main types, and you’ll select the right part every time and troubleshoot failures like a pro. Here’s what you need to know about electrolytic, ceramic disk, tantalum, and film capacitors.

Electrolytic Capacitors: You’ll find electrolytic capacitors in every power supply worth building. These workhorses deliver massive capacitance values when you need them most. They’re polarized—positive terminal goes to positive, negative to ground. Get this wrong, and you’ll create a short circuit that destroys your project. Use electrolytics for filtering, smoothing, and energy storage. Audio equipment, power supplies, DC voltage regulation—electrolytics handle it all. Always verify polarity and voltage ratings before you solder. Your circuits depend on it.

Ceramic Disk Capacitors: Ceramic disk capacitors are your go-to for reliability and performance. These non-polarized components work in any direction—no polarity concerns, no installation mistakes. You’ll use them in high-frequency circuits, RF applications, bypassing, and decoupling. They’re small, stable, and cost-effective. Every electronics pro keeps these stocked because they solve problems fast and work every time.

Tantalum Capacitors: Tantalum capacitors pack serious capacitance into tiny packages. Modern circuits demand space efficiency—tantalums deliver. Like electrolytics, they’re polarized. Connect positive to positive, negative to ground. Period. You’ll appreciate their stable capacitance and rock-solid reliability, especially in surface mount applications. But respect their voltage limits. Exceed the rating, and they’ll short out on you. Use them right, and they’ll outlast everything else in your circuit.

Film Capacitors: Film capacitors are the precision tools of the capacitor world. Low ESR, long lifespan, excellent stability—they deliver performance when accuracy matters. These non-polarized components handle AC and DC voltage with equal skill. You’ll reach for them in signal coupling, filtering, and timing circuits. Audio applications, power electronics, measurement circuits—film capacitors perform when precision counts. In terms of size compared to ceramic capacitors, film capacitors are generally larger for the same capacitance value. This size difference is due to the dielectric materials and construction methods used, making film capacitors bulkier when size compared to ceramics.

Master these four types, and you control every capacitor decision in your projects. Whether you’re measuring capacitance with your multimeter, diagnosing short circuits, or replacing failed components, this knowledge makes you the expert. Choose the right capacitor type, install it correctly, and your circuits will work exactly as designed.

Choosing the Right Multimeter

You need the right multimeter for accurate capacitor testing—period. Choose a digital multimeter with dedicated capacitance measurement mode. This feature delivers the precise readings you demand. Get a multimeter with high input impedance and low minimum capacitance range. You'll measure even the smallest capacitors with professional accuracy. Advanced digital multimeters pack a built-in discharge function—grab one. You'll test capacitors safely without risking your meter or components. Analog multimeters and specialized capacitance meters work, but a digital multimeter with clear capacitance mode, resistance mode, and voltage mode gives you maximum versatility. Master switching between these modes. You'll measure capacitance, check for shorts, and verify voltage like a pro. Always discharge the capacitor before testing—protect your multimeter and yourself.

Setting Up Your Multimeter To Measure Capacitance

Always discharge a capacitor before testing it to avoid electric shock.

To measure the farads or microfarads of a capacitor, the capacitor must first be disconnected from the circuit. It’s important to stay careful when handling capacitors connected to a circuit. You risk being shocked when touching a capacitor since it stores electrical charge. Even when the power is off, the capacitor will have stored energy. If you touch a capacitor before it has been discharged, you will be shocked or injured. When the capacitor begins to be tested, it should be fully discharged to ensure accurate results.

When a digital multimeter measures capacitance, it sends a small test current through the capacitor. This test current is related to the applied voltage across the capacitor, and the charging process follows a time constant determined by the capacitance and any resistance in the circuit. The multimeter reads this test current to determine the farads or microfarads of the capacitor. In order to accurately measure this test current, the capacitor needs to be discharged.

Let’s learn how to discharge the capacitor before removing it from the circuit:

1. Turn off power to the circuit and disconnect the voltage source before handling the capacitor. You can test if a circuit is off by measuring its voltage.

2. Once the power is turned off, begin discharging the capacitor.

3. Discharge the capacitor by touching the terminals with a known resistor, such as a 20,000 Ω, 5-watt resistor, across the capacitor terminals for a few seconds. Use insulated tools when performing this step to protect against electric shock.

4. Technicians typically touch the metal part of a capacitor with an insulated screwdriver across the two terminals to discharge it for safety. For larger capacitors, additional precautions or longer discharge times may be necessary, as they can hold a charge longer.

The time constant (RC) is the product of the resistance and capacitance in the circuit, and it determines how quickly the capacitor charges or discharges during measurement.

To set up your meter for capacitance measurement, you first need to plug your test leads into the correct ports on your digital multimeter:

• Your red lead goes into the port marked with the "–|(–” symbol. This is the capacitor symbol.

• Your black lead is plugged into the port marked with “COM”.

Digital multimeter displaying microfarads.

Afterwards, you need to set your multimeter dial to the capacitor symbol for capacitance measurement:

1. Rotate the dial until it points at the  "–|(–” capacitor symbol. This capacitor symbol is universal on all multimeters for capacitance measurement.

2. On some multimeters, you might need to use the yellow function key to set the multimeter to the capacitance symbol instead. This is because each dial position on a multimeter can have multiple measurements. Press the yellow function key until the "–|(–” capacitor symbol appears on your display. 

Safety Precautions and Best Practices

Master capacitor safety and you master the fundamentals. When you work with capacitors and digital multimeters, you follow proven safety protocols. Period. These guidelines protect you and deliver accurate measurements every single time.

• Always discharge the capacitor: You discharge that capacitor before you touch it. No exceptions. Stored electrical charge will shock you — we prevent that. Grab a resistor, place it across those terminals, or use a proper discharge tool. Simple. Effective.

• Use the right test leads: Quality test leads make quality measurements. You connect them securely to your meter and capacitor terminals. Loose connections give you bad readings and dangerous short circuits. We don't accept either.

• Set the correct measurement mode: Your digital multimeter has one job — measure capacitance correctly. You set it to capacitance mode before you start testing. Wrong settings damage your meter and waste your time.

• Be cautious with high voltage capacitors: Large electrolytics and film capacitors pack serious voltage punch. They store power even after circuit removal. You check that voltage rating and handle them with respect. High voltage demands high caution.

• Handle components gently: Electrolytics don't forgive rough treatment. You avoid bending leads and applying excessive force. Damaged components give false readings and cost you money. Gentle hands, accurate results.

• Wear protective equipment: Smart technicians wear safety glasses and insulated gloves. High voltage capacitors and large caps can fail without warning. You protect yourself because accidents happen fast.

• Verify the capacitance value: You measure before you install. Your digital multimeter or dedicated capacitance meter confirms the exact value. Right component, right circuit, right results. No guessing.

• Follow manufacturer instructions: Your multimeter manual contains the answers. Specific capacitor types — ceramic disk, tantalum, film — require specific approaches. You read the instructions and follow them completely.

• Know your capacitor types: Ceramic disk capacitors behave differently than tantalum capacitors. Film capacitors have their own characteristics. You learn these differences and apply the right techniques. Knowledge prevents mistakes.

• Regularly calibrate your meter: Precision requires maintenance. You calibrate your digital multimeter according to manufacturer schedules. Accurate tools deliver accurate measurements.

You follow these practices and you get safe, accurate, reliable results. Your safety comes first. Your measurements come out right. Your components stay protected. This is how professionals work with capacitors — no shortcuts, no compromises.

Taking Capacitance Measurement With A Multimeter

Making Sure You're Set Up

1. Turn off the power to the circuit.

2. Discharge the capacitor.

3. Remove the capacitor from the circuit.

4. Confirm that test leads are in the right location: your black lead should be plugged into the “COM” port and your red lead should be plugged into the port marked with the capacitor symbol "–|(–”.

5. Set your dial so that the arrow points to the "–|(–” capacitor symbol. Otherwise, make sure to use the function key to set your meter to the capacitor symbol instead.

Measuring Capacitance

Remember to remove the capacitor from the circuit. To stay safe, wear insulated gloves and safety glasses when handling any type of electrical equipment.

Measuring Capacitance

Place one lead of the test lead on each terminal of the capacitor. For polarized capacitors, connect the red probe to the positive terminal and the black probe to the negative lead. Be sure that your hands do not touch the capacitor. This can interfere with the measurement. As you touch the test leads to the capacitor, a value will appear on the display. When a steady value is being displayed on the multimeter screen, that is your capacitance measurement. Note the units displayed on the meter. For example, the meter might display microfarads.

If you are using the resistance mode on your multimeter to test the capacitor, a healthy capacitor should initially show a low resistance reading, then the resistance reading should rise quickly towards infinity as the capacitor charges. If the multimeter displays an infinite resistance reading, the capacitor may be open and is likely faulty. If the multimeter shows zero resistance, this indicates a short circuit in the capacitor, meaning it is defective.

Some multimeters require you to manually set the range of your measurement. If your multimeter is not auto ranging, you may need to adjust your range until you get an accurate result. Do this by slowly turning the dial to a lower range setting. Stop once you have an accurate read out.

Advanced Testing Techniques

You want real answers about your capacitor's health? Go beyond basic capacitance measurement. Use impedance analysis — it reveals hidden defects that simple tests miss. Measure your capacitor's impedance across multiple frequencies. You'll catch degradation before it kills your circuit. Time constant measurement is another power move. Track how long your capacitor takes to charge or discharge through a known resistor. This exposes high equivalent series resistance (ESR) and shows you exactly how your capacitor behaves in real conditions. Yes, these techniques need specialized equipment and solid expertise. But they're worth every effort when you're troubleshooting complex problems or verifying a capacitor for critical applications. Master the time constant and discharge behavior. You'll spot subtle faults before they wreck your circuit's performance.

Troubleshooting and Repair

When your circuit fails, you troubleshoot capacitors systematically. You save time and prevent damage. Start by identifying the symptoms—malfunctioning circuits, blown fuses, visible capacitor damage. Grab your digital multimeter. Measure capacitance, voltage, and resistance. These readings tell you exactly what's wrong. You find a capacitor with values far from rated specs? Replace it immediately. Short circuit or open circuit readings? Replace that component with the exact same type and value. You've swapped the faulty capacitor—now inspect the entire circuit. Look for other issues that caused the failure. Check and maintain your capacitors regularly with that multimeter. Your electronic devices stay reliable and efficient.

---

Don't stop here! Learn everything you need to know about the skilled trades. Click here to download SkillCat and get started!

---

Conclusion

Master capacitance measurement with your digital multimeter. You need this skill. Select the right mode. Discharge that capacitor first. Handle every component with precision. You'll nail the capacitance value every time—electrolytic, ceramic, or film capacitor doesn't matter. Use capacitance mode or resistance mode for spot-on results. Test regularly. Catch faulty capacitors before they wreck your circuits.

Discharge the capacitor before testing. Always. This protects you and your gear. Get serious about troubleshooting? Grab an ESR meter or smart tweezers. These tools give you the real story on capacitor health, especially with surface mount and high-value components. Practice makes you sharp. You'll read that multimeter like a pro, spot problems fast, and keep your electronic devices running strong. Check your multimeter manual. Follow the manufacturer's specs. Master these techniques. Your circuits stay efficient, safe, and bulletproof.

FAQs

What is capacitance?

Capacitance refers to the ability of a system (like a capacitor) to store electrical charge. The unit of capacitance is the farad (F), although microfarads (µF) are often used for more precise measurements in smaller components.

How do I measure capacitance with a multimeter?

To measure capacitance, first, ensure the capacitor is disconnected from the circuit. Then, discharge the capacitor, plug the multimeter leads into the correct ports (red lead into the port marked with the capacitor symbol “–|(–”), and set your multimeter to the capacitance measurement mode. Place the leads on each terminal of the capacitor and read the measurement on the multimeter.

Do I need to remove the capacitor from the circuit?

Yes, to accurately measure the capacitance, the capacitor must be removed from the circuit. Capacitors in a circuit could potentially interfere with the multimeter's reading.

How do I discharge a capacitor before measuring its capacitance?

Discharge the capacitor by placing a 20,000 Ω, 5-watt resistor across the terminals for about five seconds. Alternatively, technicians often use an insulated screwdriver to short the terminals, discharging the capacitor safely.

Why do I need to discharge the capacitor before measuring capacitance?

Discharging the capacitor ensures safety and prevents any stored electrical charge from interfering with your measurements or potentially causing a shock.

Can I use an analog multimeter to measure capacitance?

Yes, but for capacitance measurements, digital multimeters tend to provide more precise and clearer readings. Analog multimeters might require more manual adjustments and are less accurate for small values of capacitance. An ohm meter function on an analog multimeter can be used to check for short circuits or open capacitors.

What should I do if my multimeter doesn't display a steady value?

Ensure the capacitor is disconnected from the circuit, discharged, and that you're using the correct leads and settings. If your multimeter has a manual range, try adjusting it until the reading stabilizes.

Can I measure capacitance of electrolytic capacitors?

Yes, electrolytic capacitors can be measured with a multimeter, but note that they tend to have a wide tolerance range. Always ensure the electrolytic capacitor is discharged before measuring.

What is the unit of measurement for capacitance?

Capacitance is typically measured in farads (F), but for smaller components, microfarads (µF) are more commonly used.

What is the capacitor symbol on my multimeter?

The capacitor symbol on your multimeter looks like “–|(–”. This symbol is used to set the multimeter to capacitance measurement mode.

What’s the difference between microfarads (µF) and farads (F)?Microfarads (µF) are a smaller unit of capacitance, commonly used for measuring smaller capacitors. One microfarad is equal to one millionth of a farad (1 µF = 1 x 10^-6 F).

Can I measure the capacitance of a polarized capacitor with a multimeter?

Yes, you can measure a polarized capacitor with a multimeter, but it's important to connect the red lead to the positive terminal and the black lead to the negative terminal. Always ensure the capacitor is discharged before measuring.

Can I measure capacitance in a circuit with the power on?

No, always make sure the power is turned off before measuring capacitance. Measuring capacitance in a live circuit can be dangerous, potentially causing harm to you and damaging the multimeter.

Quiz

Question #1: What is the unit of measurement for capacitance?

1. Amperes

2. Ohms

3. Farads

4. Volts

Click for the answer...

Answer: Farads

Capacitance is measured in farads (F), though microfarads (µF) are commonly used for smaller components.

Question #2: Why must a capacitor be discharged before measuring its capacitance?

1. To ensure a stable reading

2. To prevent the multimeter from being damaged

3. To avoid electrical shock

4. To increase the accuracy of the measurement

Click for the answer...

Answer: To avoid electrical shock

Capacitors can store electrical charge, which can cause a shock if touched before being discharged.

Question #3: What symbol should you look for on a multimeter when measuring capacitance?

1. Ω (Ohm symbol)

2. V (Voltage symbol)

3. A (Ampere symbol)

4. –|(– (Capacitor symbol)

Click for the answer...

Answer: –|(– (Capacitor symbol)

The capacitor symbol “–|(–” is used to set the multimeter for capacitance measurement.

Question #4: What is the first step in preparing your multimeter to measure capacitance?

1. Set the multimeter to resistance mode

2. Set the multimeter to voltage mode

3. Plug the test leads into the correct ports

4. Turn on the power to the circuit

Click for the answer...

Answer: Plug the test leads into the correct ports

The red lead should be plugged into the port marked with the capacitor symbol, and the black lead should go into the “COM” port.

Question #5: What should you do if your multimeter doesn't automatically range for capacitance?

1. Switch to a different multimeter

2. Set the range manually by adjusting the dial

3. Wait until the reading stabilizes

4. Measure capacitance again

Click for the answer...

Answer: Set the range manually by adjusting the dial

If your multimeter is not auto-ranging, manually adjust the range to find an accurate reading.

Question #6: What safety precaution should you take when measuring capacitance in a circuit?

1. Always wear gloves and safety glasses

2. Only use the multimeter’s auto range setting

3. Ensure the capacitor is in the circuit when measuring

4. Keep the capacitor connected to the circuit

Click for the answer...

Answer: Always wear gloves and safety glasses

Safety precautions like wearing gloves and safety glasses help protect you from potential hazards during measurement.

Question #7: What does the multimeter display when you measure capacitance?

1. Resistance value

2. A steady capacitance value

3. The voltage across the capacitor

4. The circuit’s current flow

Click for the answer...

Answer: A steady capacitance value

Once the multimeter is correctly set up, it will display a steady capacitance reading in microfarads or farads.