Which of the following is a type of capacitor?

• A. Electrolytic
• B. Non-polarized
• C. Variable
• D. Ceramic

Answer: (A)

Capacitors are grouped by how they’re built and what dielectric they use. An electrolytic capacitor is a specific construction that forms a dielectric oxide layer on a metal electrode and uses an electrolyte as the other terminal. This combination lets electrolytics achieve very large capacitance values in a compact size, which is why they’re so widely used for filtering and smoothing in power supplies. They are polarized, so the positive lead must be connected to the higher voltage and reversing polarity can cause failure.

Non-polarized describes whether a capacitor can safely handle reverse voltage; many capacitor types can be non-polarized, but that’s more a property than a distinct construction family. A variable capacitor is a device whose capacitance can be adjusted, typically with a mechanical mechanism, and ceramic refers to a whole class defined by using a ceramic dielectric. Among these, the electrolytic type stands out as a defined capacitor family built with electrolyte and oxide dielectric.