How to Tell Positive and Negative on a Capacitor

Capacitors on a circuit board
There are different types of capacitors, but only one type is polarized: the electrolytic capacitor. Compared to non-polarized capacitors, electrolytic capacitors are more expensive and have to be installed in a specific direction to function properly, but they have higher capacitance — or the ability to hold more charge. Read on to find out how to tell positive and negative on a capacitor and to learn more about non-polarized devices.

Capacitor Polarization

When you connect voltage to an electrolytic capacitor’s terminals, the polarity must be correct or the capacitor’s oxide layer can be damaged. This creates a large current flow and the eventual destruction of the capacitor. So, how do you tell which sides are positive and negative? Most electrolytic capacitors are clearly marked with a black stripe on the negative side and include arrows or chevrons to deter incorrect connections. Unmarked polarized capacitors have an indented ring around the positive end.

Types of Non-Polarized Capacitors

Non-polarized capacitors come in different shapes and sizes. They don’t have the capacitance of polarized capacitors, but they’re cheaper and more readily available. Here are a few of the most commonly seen:

  • Ceramic capacitors
  • Silver mica capacitors
  • Polyester capacitors
  • Polypropylene capacitors
  • Teflon capacitors
  • Glass capacitors

Find the Parts You Need at Gateway Cable Company

Need assistance with choosing the right capacitor for your operation? Gateway Cable Company can help! Contact us for a quote on any of our products and to learn more about polarized and non-polarized capacitors. We’re also a reliable source for more information on other electrical components, such as twisted pair cables and terminal blocks.