We propose a simple algorithm devoted to locate the "corner" of an L-curve, a function often used to chose the correct regularization parameter for the solution of ill-posed problems. The algorithm involves the Menger curvature of a circumcircle and the golden section search method... It efficiently locates the regularization parameter value corresponding to the maximum positive curvature region of the L-curve. As an example, the application of the algorithm to the data processing of an electrical resistance tomography experiment on thin conductive films is reported. (read more)