Pot Core
The core fully wraps around the frame and windings, providing excellent EMI shielding. Pot cores conform to IEC standards, allowing for good interchangeability during manufacturing. They offer simple frame options (without pins) as well as PCB-mountable frames (with pins). Due to their design, pot cores are more expensive compared to other cores of similar size. However, their shape is not conducive to efficient heat dissipation, therefore not suitable for high-power transformer applications.
RM Core
Compared to pot cores, RM cores have symmetrical sides cut off, which improves heat dissipation and facilitates larger lead wire extraction. They save approximately 40% of installation space compared to pot cores. RM cores come in both pinless and pinned frame options and can be installed using a pair of clips. They can be flat-shaped (suitable for flat transformers or directly mounting on PCBs with pre-designed windings). While their shielding effect is not as good as pot cores, it is still decent.
EC, ETD, and EER Cores
These core types bridge the gap between E cores and pot cores. Like E cores, they provide ample space for large wire leads, making them suitable for low-voltage high-current switch-mode power supply trends. These cores also excel in heat dissipation. Their cylindrical center post reduces winding lengths and copper losses, allowing for higher output power. The cylindrical post design eliminates the risk of damaging wire insulation during winding, unlike the sharp edges of rectangular cores.
PQ Core
PQ cores are designed specifically for power supply inductors and transformers. The PQ shape optimizes the ratio between core volume, surface area, and winding area. This design allows minimal cores to provide maximum inductance and winding area utilization. It enables achieving maximum output power in the smallest transformer volume and weight while occupying minimal PCB space. Installation can be done using clips, ensuring a secure fit. The effective design also ensures a more uniform magnetic path, resulting in fewer hotspots compared to other core structures.
EP Core
The EP core features a circular central column that fully wraps the windings except for the end in contact with the PCB, offering excellent shielding. This unique shape minimizes the impact of gaps formed during the assembly of two core pieces and provides a higher volume-to-space utilization ratio.
Toroidal Core
For manufacturers, toroidal cores are the most economical option, with lower costs among comparable core types. Using a frame eliminates additional assembly costs. They are suitable for machine winding when necessary and offer good shielding properties.