About Metal Oxide Film Resistor

If you repair switch mode power supplies you will definitely have seen the metal oxide film resistor. It can range from 1/4 watt to 2 watt. Usually, if the resistor have problem we will replace it with another type of resistor i.e carbon film resistor because we think that both are the same and also not all electronics shop sell the metal oxide film resistor. One thing you wouldn't know about the replacement carbon film type is that sometime this resistor just can't be used in certain power supplies.

The moment you turn on the power supply, the whole power section will blow again. But if you replace it back with the original metal oxide film resistor the power supply will work normally. This means that in the safe side always replace it with original type of resistor. Metal-oxide film resistors are made of metal oxides such as tin oxide. This results in a higher operating temperature and greater stability/reliability than carbon film resistor.

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4 Comments

1. 

   Javier

   October 20, 2012 at 3:53 pm

   Muchas gracias profe buena informacion un saludo desde Colombia

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2. 

   yosry mostafa

   December 21, 2012 at 6:18 am

    
   hi mr jestine ,
   can you explain the difference between the carbon and metal resistors when they have the same value and power rating 
   thanks
   your student
   yosry

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   • 

     Jestine Yong

     December 21, 2012 at 6:24 am

     HI Yosry,

     The answer is in the last sentence of the second paragraph.

     Jestine

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3. 

   bijoy. India. Kerala. Trissur

   January 24, 2013 at 1:12 pm

   Thanks.
    

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