The typical electrical circuit diagrams for the FN9255 and FN9255E series are shown here. The designs are based on two-stage filtering, with the standard FN9255 model offering the highest performance. The FN9255B and FN9255EB are available without capacitors to ground; therefore they have zero earth leakage, making them ideal for medical applications. The FN9255EB (with added earth line choke) has improved performance compared to FN9255B. Both comply with IEC/EN/UL 60601-1 requirements.