electronic circuit interface of user with limitation of current voltage - current characteristic balanced out limitation and unbalanced in limitation

摘要

it is described an electronic circuit of interface between the telephone line and the telephone user which form, with the central battery (ud).a bridge of food for the telephone line (ln), with limitation of current line (a) to a predetermined threshold value (ilim).the voltage - current characteristic of bridge of balanced diet for values of current line (the) below the current threshold (ilim) and is unbalanced when the power line(a) reaches the threshold current (ilim).