royalmp2001 said:
Thanks for your help, folks....
The difference is under the conformal coating. They might look the
same, although many metal oxide resistors are made for higher voltage,
and are sometimes larger.
The metal film (or the metal oxide film) is sputtered on the body of
the resistor, and then trimmed up to value (laser trimmed or,
surprisingly on larger resistors, sometimes by simple abrading) before
being coated. The metal itself is an alloy, and the line between metal
film and metal oxide film isn't all that definite.
If you're wondering, look at the ohmic value of the resistor you're
trying to replace. If it's physically small and high ohms (over 1
meg), it's probably metal oxide. But you choose the resistor based on
the ohmic value, the wattage, the tolerance, the drift specs, and the
voltage withstand capability. The composition of the resistor metal is
what works.
Possibly you might want to offer a more descriptive question, like:
* Do you know any or all of the above choice parameters?
* Is this a repair/replacement issue, a design issue, or are you just
asking?
Good luck
Chris