What kind of fault occurs at irregular intervals in a normally functioning device?

An intermittent fault is characterized by its unpredictable nature, occurring sporadically in a device that otherwise functions properly. These faults can be challenging to diagnose since they do not present consistently and may seem to resolve on their own for periods of time, only to reappear later. This behavior often leads to frustration for technicians and engineers because the fault may not manifest during testing or troubleshooting sessions, making it hard to replicate and analyze.

On the other hand, permanent faults manifest continuously after their occurrence and are generally easier to identify since the device fails to operate correctly at all times. Critical faults lead to serious failures requiring immediate action, and consistent faults repeat regularly, making them more predictable. Thus, intermittent faults stand out due to their irregular occurrence, creating unique challenges in maintenance and repair.