Comments on ´Electro-thermal device and circuit simulation with thermal nonlinearity due to temperature dependent diffusivity´

Recently, a semi-analytical method for dealing with the transient diffusion equation for circuit simulation with temperature dependent thermal properties has been proposed by Batty and Snowden [see ibid., vol. 36, no. 23, p. 1966-8 (2000).]. However, in the derivation of the method a mistake is made which may lead to inaccurate results, especially in the case where the thermal properties vary strongly with the temperature. For the sake of convenience we shall consider the one dimensional diffusion equation without sources. The authors´ reply is included