When it is desired to detect and interrupt conditions, such as so-called arcing faults", that may be harmful to the protected circuit but are not readily sensed by thermal and electromagnetic trip units, electronic circuits such as described in U.S. Pat. No. 5,307,230 entitled Circuit Breaker With Protection Against Sputtering Arc Faults", U.S. Pat. No. 5,452,223 entitled Arc Detection Using Cu