NATE Air Conditioning and Heat Pumps Practice Exam

A good fuse typically has a reading of close to 0 ohms on an ohmmeter, indicating that it has continuous electrical conductivity and is not blown. When you test a fuse with an ohmmeter, you are measuring its resistance. A reading of 0 ohms suggests that the fuse is intact and allows current to pass through without any obstruction.

Higher resistance values, such as less than 1 ohm, might still be acceptable, but they indicate a slight resistance that could suggest wear or degradation, which might not guarantee optimal functionality. On the other hand, an infinite reading would imply the fuse is open (blown) and not allowing current to pass through at all. Lastly, a reading that rises to 0 before falling toward infinity could indicate issues with the fuse, such as intermittent connectivity, which might not make it reliable for use. Therefore, the ideal reading for a functional fuse is essentially zero ohms, confirming that it is in good working condition.