IEC 60133: Ferrite Pot Cores — The Standard Magnetic Shell for SMPS Transformers

Ferrite Pot Cores — The “Standard Shell” for SMPS Transformers and Inductors

IEC 60133:2000 specifies ferrite pot core dimensional standards. Every switch-mode power supply transformer and filter inductor uses ferrite cores — and the pot core, with its closed magnetic path and extremely low EMI radiation, is widely used in telecom and precision power applications.

Why pot cores? Compared to E-cores, the pot core winding is almost completely enclosed by ferrite, yielding minimal leakage flux — EMI radiation 10–20 dB lower than E-cores. Trade-offs: poor heat dissipation (coil enclosed), difficult winding (Litz wire must thread through small holes). Standard sizes from P9/5 (9 mm OD) to P36/22 (36 mm OD) span 1 W–500 W applications.