In this thesis magnetic circuits were simulated and experimentally validated in order to obtain maximum magnetic fields. When using iron to concentrate the flux, we deal with two areas of significant interest: The linear one, where the iron is used as an easy predictable amplifier, which increases very small fields by some magnitudes to make them measurable. On the other hand, the saturated case, in which one can produce field strengths higher than the saturation magnetization with the help of geometrical optimization. Both cases were researched with the help of numerical simulations. The results of the maximum field strength simulations were also verified by an experimental setup, which yielded results very accurate to the calculations. Magnetic fields larger than 3T could be realized.