What are the troubles for a defective resistor?

Question

What are the troubles for a defective resistor?

Answer 1

A defective resistor during the manufacturing process is one that does not meet the specifications.  Either too high or too low a resistance (outside the design tolerance) or has other physical defects such as damaged leads, illegible or miss-labeled marking, etc.  

Assuming the resistor passed the quality control at the factory, the list of things to look for when repairing a device is far shorter.

A defective resistor generally has a higher than expected resistance.  Often an open circuit.  In some instances the damaged resistor will track across the body and actually have a lower resistance.

Look for a device that appears to have discoloration due to heat damage.  Often a brown to black appearance.

There is a joke among electrical engineers that when electrical components are made, the factory puts smoke in them.  If you let the smoke out, it will no longer work.  If you subscribe to this theory, then the troubles for a defective resistor is "the smoke got out".

Answer 2

Not sure what you are asking.

A defective (burned out) resistor will usually be an open circuit. Sometimes it will be a short circuit. Rarely, you will see a value shift.

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