Capacitor Characteristics - Types of Capacitors | QuestComp.com

12 Nov, 2019 | Quest Components
Capacitor Characteristics

Capacitor Characteristics

When choosing a capacitor for your project it’s important to know the details about the capacitor you are buying to ensure you get exactly what you need. These details are referred to as characteristics. A capacitor’s characteristics are how it is identified among many different types of capacitors.

As you view various specific capacitor items on our webiste, you will find manufacturer data sheets and some basic parametric information. Take a moment to view the data sheet and review the specifications directly from the manufacturer to be sure that they align with the requirements of your application. As you read further, you will find an explanation of some of the most common and important characteristics

Here are 8 characteristics that are important to know about any capacitor.

  1. Nominal Capacitance (C). Capacitance refers to the amount of electrical energy a capacitor can store within its electromagnetic field. This value is represented in the unit Farad, including pico-Farads (pF), nano-Farads (nF), and micro-Farads (µF or sometimes uF for simplicity). Fixed capacitors have a specific capacitance that cannot be adjusted. Variable capacitors can be modified to achieve a desired capacitance within the available range of that capacitor.
  2. Working Voltage (WV). The working voltage is the maximum amount of voltage a capacitor can receive continuously without damage or failure. Voltage can be DC (direct current) or AC (alternating current). The WV printed on the capacitor itself will typically refer to the DC rather than AC. The WV is affected by temperature, as the value listed only applies within a specific temperature range. Extreme heat or cold may affect the working voltage a capacitor can withstand.
  3. Tolerance (±%). The capacitance value listed for a capacitor can sometimes vary more or less. The value can only vary by a certain range to be accepted, which is its tolerance. Tolerance can vary anywhere from real low tolerance like 1% all the way up to part with a -20% to +80% tolerance. Common tolerance values are 5%, 10% and 20%, this of course varies based on the type of capacitor it is. Capacitors are ranked in quality based on their tolerance. The lower the tolerance, the closer the actual capacitance is to the value listed by the manufacturer, thus the higher the quality of the capacitor (and oftentimes more expensive as well).
  4. Leakage Current. A capacitor contains a non-conductive material known as a dielectric. The dielectric will typically allow a small amount of electricity through, referred to as leaking. Leaking happens because of the strong electromagnetic field that exists between the plates when voltage is applied. Extremely low leakage in a capacitor, such as in a film or foil type, is said to have a high “insulation resistance” (Rp). High leakage, which is more typical in electrolytic capacitors, is referred to as “leakage current.”
  5. Working Temperature (T). Temperature affects a capacitor’s ability to store electrical energy. For example, extremely high temperatures can cause a liquid electrolyte in an electrolytic converter to evaporate and change the capacitance. In contrast, extremely cold temperatures could cause liquid or gel electrolyte to freeze and impact its capacitance.
  6. Temperature Coefficient (TC). The temperature coefficient measures the change in capacitance that could occur within a particular temperature range. As temperatures rise, some capacitors increase their capacitance values and are considered Class 2 capacitors, such as this one GRM155R71C104KA88D, and others decrease their capacitance value. Capacitors that are able to maintain their capacitance within a temperature range are considered to be Class 1, like this one CC0402JRNPO9BN101. The importance of temperature when it comes to capacitance depends on the job at hand. If you know that temperature may be an issue, the TC is an important characteristic to be aware of.
  7. Polarization. This refers to the charge of the plates within a capacitor. In most capacitors there is a positive end and a negative end, similar to a battery. When applying voltage it is necessary to match positive voltage with a positive terminal, and negative voltage with a negative terminal. Incorrect polarization can lead to severe damage within the capacitor and throughout the circuit and device.
  8. Equivalent Series Resistance (ESR). This is a term for the total resistance of every part of a capacitor that resists, rather than conducts, electric current. It includes the resistance of the plates, the dielectric, the terminal leads, and the connections to the dielectric. ESR is the sum of all of these, measured within a specific frequency and temperature. This determines energy loss for a capacitor.

Characteristics of Array/Network Capacitors

These same characteristics can apply to array/network capacitors as they typically involve sets of individual or connected capacitors. The values on sets of capacitors may include individual characteristics or total values for the set, depending on how they are packaged.

Quest Components Clearly Characterizes Capacitors for Easy Identification

Many of the characteristics and features of a capacitor are listed right on the outer casing of the capacitor itself. Additional information is available in the online description of each capacitor before ordering and also in the paperwork that comes with every capacitor purchased. There should never be a mystery when it comes to the details about a product.

Quest Components is fully transparent when it comes to characteristics and features of the products we offer. If you have any questions about a product, knowledgeable electricians are available to help. Call (623) 333-5858 today to inquire about a product or place an order. You can also search and order capacitors here. We look forward to working with you.

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