This letter represents the tolerance of the capacitor, meaning how close the actual value of the capacitor can be expected to be to the indicated value of the capacitor. If precision is important in your circuit, translate this code as follows: [13] X Research source. Read letter-number-letter tolerance values. Many types of capacitors represent the tolerance with a more detailed three-symbol system.
Interpret this as follows: [15] X Research source The first symbol shows minimum temperature. The second symbol shows maximum temperature.
The third symbol shows variation in capacitance across this temperature range. Interpret voltage codes. If multiple values could apply such as 1A or 2A , you'll need to work it out from context.
For an estimate of other, less common codes, look at the first digit. Look up other systems. Old capacitors or capacitors made for specialist use may use different systems. These are not included in this article, but you can use this hints to guide your further research: If the capacitor has one long code beginning with "CM" or "DM," look up the U. If there is no code but a series of colored bands or dots, look up the capacitor color code.
Include your email address to get a message when this question is answered. Helpful 2 Not Helpful 0. The capacitor can also list information on operating voltages. The capacitor should support a higher voltage than the circuit you use it in; otherwise, it may break down possibly explode under operation.
Helpful 1 Not Helpful 0. Many common capacitor values are near this crossover area and could be commonly referred to using either unit designation. For example, a 10, pF cap is more commonly referred to as 0. Although you can't determine capacitance by the shape and size alone, you can guess at a rough range based on how the capacitor is being used: The largest capacitors in a television monitor are in the power supply. Helpful 0 Not Helpful 0. Be very careful when handling large capacitors, which can hold a lethal amount of energy when charged.
Always make sure to discharge them first by using an appropriate resistor. Never short circuit them, as this could cause an explosion. Helpful 11 Not Helpful 9. Related wikiHows How to. How to.
More References About This Article. Co-authored by:. Co-authors: Updated: June 3, Italiano: Leggere un Condensatore. Bahasa Indonesia: Membaca Kapasitor. Nederlands: De waarde van een condensator aflezen. Thanks to all authors for creating a page that has been read , times. As I read about that particular board Panasonic EH it seems that Panasonic used cheap capacitors and it was a well known problem.
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Cookies make wikiHow better. By continuing to use our site, you agree to our cookie policy. Now compare the calculated value of the capacitance with the value of the capacitor printed on it. The discharge time can also be calculated. In this case, the time taken by the capacitor to discharge to Good to know : The time taken by a capacitor to discharge about The discharge time can be used as the same in the formula to find the value of the capacitor.
Method 6. Test the Capacitor by Continuity Test Mode. To do so, follow the simple instructions below. Method 7. It is the basic approach to determine the defective capacitor without a multimeter by observing the apparent signs appearing on it.
The capacitor is failed and damaged if you find any of the following conditions. Bulging Top Vent of Capacitor. The top vent of the electrolytic capacitor in shape of K, T or X are the weak points made to release the pressure during the failure of a capacitor to avoid serious damage to the surrounding and any other components connected near to it.
If you find a bulging top of the capacitor, it is the electrolytic discharge black, white, orange color which depends on the electrolytic material i. Bulging Bottom and Lifted Case of Capacitor. If the produced gas pressure does not break the top vent of the capacitor during failure, it goes through the bottom and pushes the rubber which makes the bottom bulge and lifts the case.
If you find the following signs on ceramic or tiny SMD capacitors, they are faulty and need to be changed with the correct ones. Broken or cracks in the casing. Damaged or any sign of burnt casing. A hole in the casing. Broken terminals. How to Test a Battery with Test meter? Method 8. Note: Not Recommended for everyone but professionals only.
Please be careful to do this practice as it is dangerous. Please follow the safety precautions and warnings before applying this method.
This is only applicable in an emergency where replacing the capacitor with a proper value is important and there are no other options to check the damaged capacitor. If you are not sure, because serious damages may occur during this practice follow the other options 1 — 7 as alternative methods to troubleshoot the capacitor.
The resistor should be connected in series with battery and capacitor positive terminals. This way, it will reduce the excessive current while charging the capacitor. In case of absence of DC source like batteries , the high rated capacitors i. This way, it will reduce the charging and discharging current. Here is the step by step tutorial on how you may check a capacitor by this method. Note : Keep in mind that a polar capacitor should not be connected to the AC supply.
On the other hand, a non-polar capacitor can be attached to the DC supply because, they are back to back electrolytic capacitors.
As we know that capacitors block DC but let pass the AC but still it will charge with the DC supply source until it reaches the terminal voltage level. Sir, Thanks lot for sharing this hand on experience for checking capacitor. Thanks again Pls upload rest components testing also in same way. Regards Rajender India. The mathematical expression of how to come about the rang limit in which the capacitance fall in to. Thanks for the information. How do l change direction of a capacitor start capacitor run induction motor.
Really Dangerous. As a practicing engineer, I would never do this. There will be a dedicated tutorial on how to discharge a capacitor but for the time being, let us go through both these methods very briefly. WARNING: This method is not preferred especially if you are beginner as there will be sparks generated while discharging, which might cause burns or other damage. Use this method as a last resort.
If the capacitor is in the circuit on the PCB , then properly de-solder it and make sure not to touch the terminals of the capacitor. Now, take an insulated screwdriver with a longer handle and hold it in one hand. Take the capacitor in the other hand and touch the metal part of the screwdriver to both the terminals of the capacitor.
You will see sparks and hear some crackling sound as an indication of electric discharge. Repeat a couple of time to make sure that the capacitor is completely discharge. Now, we will see a safe way to discharge the capacitor. This method is often used in power supplies and other similar circuits where a Resistor, known as a Bleeder Resistor, is placed in parallel to the output capacitor so that when the power is turned off, the remaining charge in the capacitor is discharged through this resistor.
Take a large value resistor usually, few kilo Ohms with a high power rating like 5W and connect it across the terminals of the capacitor. Instead of directly connecting, you can make use of wires with crocodile clips on both the ends.
The capacitor will slowly discharge and you can monitor the voltage across the terminals of the capacitor with a multimeter.
Use this tool as a starting point. Also, the power rating of the resistor should be at least 2. This is one of the easiest, quickest and accurate way to test a capacitor.
For this, we need a Digital Multimeter with Capacitance Meter feature. Most of the mid and high end Digital Multimeters include this functionality.
The capacitance meter on the digital multimeters often display the capacitance of the Capacitor but few meters display other parameters like ESR, leakage, etc. Using this method, capacitors ranging from few nano Farads to few hundreds of micro Farads of Capacitances can be measured. Even with these Multimeters, we can test a Capacitor. This method of testing the capacitor might not be accurate but can differentiate between a good and bad capacitors.
This method is applicable only if the capacitance value is known and if we want to test whether a capacitor is good or dead.
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