Note 1 to entry: The disappearance may be due to self-recovery.

Note 2 to entry: In IEC 60050-191:1990 (now withdrawn; replaced by IEC 60050-192:2015), this concept was termed "intermittent fault", with "volatile fault" and "transient fault" as synonyms, but not all transient faults are intermittent faults (192-04-06).

Note 3 to entry: IEC 60050-191:1990 (now withdrawn; replaced by IEC 60050-192:2015) identified “volatile fault” as a synonym, which is deprecated as it is not true in all applications.