types of resistors, carbon film vs. metal film

[Zellarman]

Between carbon and metal film resistors, which is better or more durable, what are the benefits of one over the other? Specifically I'm using the resistor to control current on an LED lighting circuit.

 

[poor mystic]

If you connect a high voltage across a low-resistance metal oxide film resistor in an oxidising environment, the resistor will begin to burn, so that more metal is converted to metal oxide in the surface of the resistor, and resistance rises and limits current to a value which will not cause further burning. The final resistance is a function of the driving voltage.
You can't do that with a carbon resistor.

PS
you want metal film resistors in your application. They are much smaller units, yet can dissipate more power. Carbon resistors are mostly used at very high frequencies, because of their lower self-inductance.

 

[davelectronic]

The metal film resistors will also have a closer tolerance for circuits where the resistance value needs more stability over its range and rating.
Dave.