The single-phase rectifier filter circuits, including the half- and full-wave rectifiers with a capacitor and full-wave rectification with either a series inductor or a choke-input filter, have been analyzed taking into account the voltage drop across the tube and the transformer. In these analyses the high-vacuum thermionic diode was considered. The voltage-current characteristic curve of a diode was assumed linear, and the equivalent resistance of the tube was chosen equal to the reciprocal of the slope of the diode characteristic curve in the conducting region. For the capacitive filtering case, the equations expressing the ignition angle, the extinction angle, and the ratio of the d-c output voltage to the peak value of the applied voltage when the steady state condition is reached have been derived. It was found that these equations not only depend upon the product of the angular frequency of the applied voltage and the time constant of load circuit, but also depend on the ratio of the load resistance to the equivalent resistance of the tube and the source transformer. Most of these equations appear to be of a transcendental form, the solution of which requires either graphical or trial-and-error method. Both of these require tedious work and are time consuming with hand computations. However it is easily accomplished today by the use of an IBM 7040 computer. The calculated curves showing the variation of the ignition angle, the extinction angle, and the ratio of the d-c output voltage to the peak value of the supply-voltage for half- and full-wave rectifications were plotted with wRC as abcissa for several different values of the ratio of the load resistance to the equivalent resistance of tube and transformer. The equations derived for the direct output voltage of the rectifier circuit with either the series inductor or the choke-input filters show that they depend only on the ratio of the load resistance to the total resistance of the tube, the transformer, and the inductor. All the equations mentioned above had been experimentally verified. It is found that the calculated results checked closely with the experimental data if the equivalent resistances were properly chosen. The effect of circuit parameters on the behavior of rectifier circuits operated with three types of filters have been discussed. It becomes evident that the tube and the transformer resistance of practical circuits appears as an additional parameter which cannot be neglected in t4e analysis of the single-phase rectifier. However, inclusion of this resistance greatly complicates the analysis. The method of analysis presented in this paper may be extended to other types of rectifier circuits. Although the analysis made in this paper did not take into account all of the possible factors which may be involved in the practical circuits, nevertheless the results were presented in convenient form for practical use. / M.S.