Two theoretical models have been applied to neodymium doped triglycine sulphate (Nd-TGS) hydrogen bonded crystal pseudo spin and derived local field frequency, shift and width, polarizability, microwave absorption, acoustic wave absorption, quality factor, photo-electric sensitivity and electric resistivity in good agreement with the experimental results. Due to the similar mechanism in crystal dynamics of all hydrogen bonded ferroelectric materials, we are able to apply a common model over the crystal structure with some contemporary modifications according to different crystal lattice. By this method we can derive different relations for ferroelectric crystals even in with biased condition. We have applied the two theoretical models i.e., pseudo spin lattice coupled mode model and Ising spin model with Green's function method to Nd-TGS to derive different expressions for the dielectric, acoustic, photothermal and electric properties.