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.

This mixture is then compressed into a cylindrical shape. Their resistive elements are commonly lengths of wire usually an alloy such as nichrome nickel chromium or manganin copper nickel manganese wrapped around a ceramic or glass fibre rod or tube and coated in an insulating flameproof cement film. Composition resistors are produced using a mixture of a finely ground insulator and conductor. Typical resistance values are in the range from 1ω til 10 kω.

However even this description is out of date. The resistor is made by taking an alumina or ceramic substrate. The resistance is controlled based on the ratio of the insulator and conductor mixture. The end connection electrode bases are then placed onto this and then this is fired to ensure they are robustly held in place.

Tcr varies from 75 till 200 ppm c. They are most often wire wound resistors. Metal film resistors are produced by depositing a resistive element on a high grade ceramic rod. It is a nickname for the heat resistant ceramic case in which a coil of resistance wire is potted.

Wirewound resistors are very variable in construction and physical appearance. 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. This resistor consists of two terminals like a normal resistor. The construction of a resistor is shown in the below diagram.

The ceramic coating combines a high insulation and physical protection with good heat dissipation. Cement resistor only describes the appearance of common power resistors like that shown above. Terminals are attached and the insulation coating is applied to the outside.