What is a characteristic of fixed capacitors?

Fixed capacitors are characterized by their stable capacitance value, which does not change during operation. They are typically constructed with conductive plates that are separated by a dielectric material. This design ensures that the plates and the dielectrics are firmly together, allowing for consistent electrical performance and reliability.

The construction of fixed capacitors is intended for applications where a specific capacitance is required, without the need for adjustment. This solid construction contributes to their durability and effectiveness in various electronic circuits, making them suitable for a wide range of applications including filtering, coupling, and decoupling in both AC and DC circuits.

While the other options discuss aspects that may contradict the nature of fixed capacitors or pertain to different types of capacitors, the key feature of fixed capacitors rests in their firm construction of plates and dielectrics, lending to their predictable behavior and application in electronics.