Unit 5 - Key Terms (1)

Metal film resistor

A fixed resistor constructed by applying a film of metal to a ceramic rod in a vacuum. - Resistance is determined by the type of metal used and thickness of the film - Typical film thickness is 0.00001 to 0.00000001 inch - DO NOT change value with age - Tolerance generally better than carbon resistors - Tolerance range (2% to 0.1%) - Costly

Carbon film resistor

A fixed resistor made by coating a ceramic rod with a film of carbon instead of metal. - Less expensive to manufacture than metal film resistors - Have a higher tolerance rating than composition carbon resistors

Metal glaze resistor

A fixed resistor made by combining metal with glass then applied to a ceramic base as a thick film. - Similar to the metal film resistor - Resistance is determined by the amount of metal used in the compound - Tolerance ratings of (2%) and (1%) common

Composition carbon resistor

A fixed resistor made from a compound of carbon graphite and a resin bonding material. - Proportions of carbon and resin material determine the value of resistance - Enclosed in case of non-conductive material with conducting leads - Very popular for most applications because they are inexpensive and readily available - Made in standard values that range from 1 ohm to 22 Megohms - Obtained in power ratings of (1/8), (1/4), (1/2), (1) - Change value with age/overheated - Generally increase in value

Wire-wound resistors

Fixed resistors that are made by a winding a piece of resistive wire around a ceramic core. Resistance is determined by: 1. The type of material used to make the resistive wire 2. The diameter of the wire 3. The length of the wire - Found in various case styles and sizes - Generally used when a high power rating is needed

Fixed resistors

Resistors that only have one ohmic value, which cannot be changed or adjusted. - Several different types