What Are Wirewound Resistors?
Wirewound resistors are resistors with a structure in which resistors, which are electric heating wires, are wound around a porcelain material.
There are various types and characteristics of resistors, and they are used according to their applications and purposes.
Types of resistors:
- Chip resistors: Resistors mounted on the surface of a substrate.
- Carbon film resistors: Resistors with a carbon film formed on the surface of a porcelain material as a resistive element.
- Metal film resistors: Resistors with the same structure as carbon film resistors but using metal such as nichrome as a resistive element.
- Metal oxide film resistors: Resistors using metal oxide such as tin oxide as a resistive element.
- Metal-glass film resistors: Resistors using a mixture of metal and glass as a resistive element
- Wirewound Resistors: Resistors using a heating wire in a porcelain material.
Applications of Wirewound Resistors
Wirewound resistors are resistors consisting of an electric heating wire wound around a porcelain material, and have a low temperature coefficient and good heat resistance. They have a low temperature coefficient and good heat resistance. They are also used as resistors for current detection because they have relatively low current noise and resistance values.
The disadvantage of wirewound resistors is that they have an inductance component due to the structure of the resistor wire wound on a bobbin, and their high-frequency characteristics are not very good. The resistance value is adjusted by the wire type and number of turns, and resistors with higher resistance values are larger and more expensive.
Principle of Wirewound Resistors
Wirewound resistors have a structure in which electric heating wire is wound around them. They are characterized by their ability to obtain large power at low resistance values and are used in resistors for current detection. There are several types of wire-wound resistors, depending on the type of case.
1. cement resistors
Wirewound resistors and other types of resistors are placed in a ceramic case and sealed with cement. They have excellent insulation and heat resistance from the structure. The disadvantage is that high frequency characteristics are not good because of the inductance component as with wire-wound resistors.
2. Metal Clad Resistors
This type of resistor consists of wirewound resistors with metal cladding. Wirewound resistors are equipped with a metal cladding such as an aluminum case with heat dissipation fins to provide excellent resistance to environmental changes (heat resistance, physical properties, pressure resistance, and insulation).
3. Holo Resistors
This resistor is made by winding a resistance wire around a ceramic core and baking enamel over it to enhance heat resistance. Enameled resistors are suitable for handling large amounts of power due to their extremely high heat resistance. The disadvantage is that, like other resistors, it has an inductance component due to its wire-wound resistance, and its high-frequency characteristics are not good.