This paper presents a study of using two potential formulations-the A ^z.ast;-A formulation, and the T, Φ - Φ formulation-to solve the TEAM problem No. 27 (Eddy Current NDT and Deep Flaws). A procedure to determine arbitrary periodic excitation signal by using Fourier series will also be shown. The numerical results are compared with the experimental waveforms. The goal of this work is to find the more precise and the faster formulation and to approximate the response of a linear electromagnetic system, when the excitation is a periodic signal.