Cores Used by Butler Winding: POT Cores

Pot cores are known for their excellent shielding capability. This occurs because the core completely surrounds the coil except for two narrow slots which leads are brought  through. Pot cores have round center leg and two nearly semicircle outer legs. The center leg is usually hollow but may be solid. Solid ones run cooler because it permits a lower flux density. The center legs may be ground to provide a gapped core. An insert may be placed in a hollow gapped core to provide a means to adjust the inductance of the core (and its windings). There are popular in tuned circuits. The adjustment allows one to compensate for core tolerances and tuning capacitor tolerance.

The round slab “Pot” cores are similar to the standard round “Pot” core but differs because a portion of the core has been removed from the standard round core design. Consequently, the round slab pot cores have better heat dissipation and have more room for wire leads. Double slab (DS) “Pot” cores have two portions of the core removed. In essence the slab “Pot” cores are a compromise design between a standard “Pot” core design and a “E-E” core design.

Square “Pot” core designs differ from standard round “Pot” core at the outer legs. The outer legs have a more “corner-like” appearance to them. This shape permits tighter packing of the cores on a printed circuit board, achieving about a 40% saving in mounting area. The coil is more open hence heat dissipation and lead wire space is better that of the standard round “Pot” cores, but shielding capability is less.

Pot cores are made almost exclusively in ferrite materials.

Core Types Used by Butler Winding