Ceramic Resistor Construction

The majority of the power wirewound resistors have a ceramic core and a ceramic coating to protect the winding.

Ceramic resistor construction.

The end connection electrode bases are then placed onto this and then this is fired to ensure they are robustly held in place. Terminals are attached and the insulation coating is applied to the outside. The ceramic coating combines a high insulation and physical protection with good heat dissipation. The construction of a resistor is shown in the below diagram.

The construction of a carbon film resistor can be done by placing the carbon layer on a substrate of a ceramic. However even this description is out of date. The carbon film is a resistive material toward the flow of current in this resistor. This resistor consists of two terminals like a normal resistor.

Composition resistors are produced using a mixture of a finely ground insulator and conductor. It is a nickname for the heat resistant ceramic case in which a coil of resistance wire is potted. The construction of ceramic composition resistors concentrates nearly all of the component mass into the resistive element resulting in a rugged device with high energy capacity. The resistor is made by taking an alumina or ceramic substrate.

Metal film resistors are produced by depositing a resistive element on a high grade ceramic rod. They are most often wire wound resistors. This mixture is then compressed into a cylindrical shape. The resistance is controlled based on the ratio of the insulator and conductor mixture.

Then a thin film of resistive material is deposited this is typically metal oxide or a metal film again the resistor is fired. Cement resistor only describes the appearance of common power resistors like that shown above. Typical resistance values are in the range from 1ω til 10 kω.