An analysis of the electronic specific heat and the thermodynamic critical magnetic field as a function of the temperature is carried out in the cases of gap with isotropic-s, d ands+idsymmetries. While the isotropic-s gap shows an exponential attenuation in the electronic superconducting specific heat for low temperatures(T≪Tc)the d-wave gap presents a quadratic dependence in a wide range of temperatures and goes through a maximum atT<1&hthinsp;K.In the case of thes+idmixing a double peak transition has been obtained from the numerical computations. In theCen(T)/Tdependence a maximum at a certain temperatureT*is obtained which moves to the side of high temperatures when the Fermi level is far away from the van Hove singularity. The temperature dependence of the critical magnetic field presents a great departure from the parabolic law in the case of an isotropic-s gap while in the d-wave case, the mentioned dependence approaches the parabolic one. ©1999 American Institute of Physics.