What Size Capacitor Do I Need?

Physical Size

• Plastic- and ceramic-based capacitors, often found in small electronics, may measure only a few centimeters long, while capacitors found in industrial machines may be measured in inches and pounds. Because of the simple makeup of most capacitors, physical size is generally a nominal factor. When installing a new capacitor inside of a small case or onto a cramped circuit board, you'll want to look for the smallest capacitor that complies with your circuitry's power specifications.

Voltage and Capitance

• The power ratings are the most important size factor to consider when searching for the right-size capacitor. The capacitor's voltage describes how much power the capacitor can output, while the capacitance specifies the amount of power the capacitor can store. When selecting a capacitor, you'll need to select one with a voltage that matches your power source and a capacitance that will sustain your voltage for the desired amount of time.

Sizing Guides

• Because of the small size of many capacitors, their power ratings may not always be printed on them. But if you need to identify a capacitor's specifications so that you can replace it with a capacitor of the same size, you can reference a capacitor size chart. You can compare the capacitor's letter or color marking with a size chart to find out the capacitor's voltage and capacitance.

Considerations

• If you've identified the specifications required of your replacement capacitor, you can order the capacitor from an electronics retailer. But if there is any doubt about the correct size of the replacement capacitor, visit a local electronics store to ensure that you pick up the right-size capacitor. Television repair shops and small electronics store are good locations to begin inquiries about your capacitor.