Designing a core can be complicated and usually falls on the designer to create, even though it is not the designers specialty. Allegro has developed a modeling knowledge to help the customer so that they can design the proper core dedicated for their application, and get the best performance that fit their requirements. Careful attention must be paid to the core design because the efficiency of a concentrator, and thus of the current sensing system, crucially depends on the core material, dimensions, air gap, and geometry. The core material must balance between its permeability, resistivity, and cost, and is typically from the families of iron alloys such as ferrosilicon (FeSi) or ferronickel (FeNi) core-based solutions and can be optimized for size and performance depending on these parameters and the customers current sensing range, accuracy, or hysteresis requirements for example.