Resistors, like many electronic components,  come in a variety of types, shapes, sizes, capacities, and each has significant differences in typical values for resistor wattage rating,  tolerances, temperature coefficient, noise, voltage coefficient, frequency response, size, and reliability. Film resistors are most used ones in circuits and consist of
carbon composition resistors, carbon film resistors, thick film resistors, thin film resistors and metal film resistors. Take the last two for instance.
 
Borrowing from semiconductor processes, thin film resistors are made through a vacuum deposition process called sputtering where a thin layer of conductive material is deposited on an insulating substrate. This thin layer is then photoetched to create a resistive pattern.


By precisely controlling the amount of material deposited and the resistive pattern, tolerances as tight as 0.01% can be achieved with thin film resistors. Thin film resistors are limited to about 2.5 watts and lower voltages than other resistor types but are very stable resistors. There is a price for the precision of thin film resistors which generally are twice the price of thick film resistors.
 
When mentioning film resistor, we take metal film resistors into account. They are very similar in construction to carbon film resistors, with the main difference being the use of a metal alloy as the resistive material rather than carbon.

 
The metal alloy used, typically a nickel-chromium alloy is able to provide tighter resistance tolerances than carbon film resistors with tolerances as tight as 0.01%. Metal film resistors are available up to about 35 watts, but resistance options begin to diminish above 1–2 watts. Metal film resistors are low noise, and stable with little resistance change due to temperature and applied voltage.