A wirewound resistor is a common type of resistor consisting of a metal (usually nickel alloy) wire wound around a core material. It is the most common type of power resistor. The core material is typically made of ceramic, which provides the necessary insulation and support structure. Wirewound resistors are designed to have a low resistance value and high power dissipation, making them a good choice for applications that require a stable, reliable source of power, such as power supplies. They are also often used for precision applications, since the resistance can be very accurately calculated based on the number of turns in the wirewound.