Which type of capacitor is known to be polarity sensitive?

Electrolytic capacitors are known to be polarity sensitive because they have a particular construction that includes an anode and a cathode. In an electrolytic capacitor, one terminal is made of a metal that is usually aluminum or tantalum and is coated with a thin layer of oxide. This oxide layer acts as the dielectric. The other terminal, which is typically made of a conductive electrolyte, is inherently tied to the direction of current flow.

If an electrolytic capacitor is connected in reverse polarity, it can lead to catastrophic failure, often resulting in the release of gas, leakage, swelling, or even explosion due to the breakdown of the dielectric layer. Therefore, it is crucial to observe the proper polarity when installing these components in a circuit.

In contrast, the other types of capacitors mentioned, such as film capacitors, variable capacitors, and supercapacitors, are not polarity sensitive. Film capacitors, for example, can be connected in any direction, and variable capacitors can also function regardless of terminal orientation. Supercapacitors, while they also have specific requirements for maximum voltage and leakage, are constructed to handle connections in both polarities without such strict limitations as seen with electrolytic capacitors.