| 摘要 |
367,056. Valve amplifying circuits. HAMMOND, J. H., Hesperus Avenue, Gloucester, Massachusetts, U.S.A. Nov. 21, 1930, No. 35176. Convention date, Nov. 23, 1929. Addition to 366,937. [Classes 40 (iii) and 40 (v).] In an amplifier for gramophone reproduction or the like as described in the parent Speci. fication the means to control the gain in accordance with the intensity and to prevent over. loading are applied to push-pull amplifiers. The Figure shows a three-stage amplifier the bias for the stage 27, 28 of which is controlled by the input of intermediate frequencies to that stage, the low frequencies being removed by small condensers 50, 51 and the high frequencies by the filter 59. The output through filters 64, 65 and rectifiers 61 controls the grid bias of the input stage 25, 26 so as to prevent overloading. |
