| 摘要 |
458,450. Valve circuits. MARCONI'S WIRELESS TELEGRAPH CO., Ltd., Electra House, Victoria Embankment, London, and KEALL, O. E., 32, Rainsford Avenue, Chelmsford, Essex. June 21, 1935, No. 17929. [Classes 40 (iii) and 40 (v)] Resistance-coupled amplifiers for frequencies as low as 0À1 c. /sec. and suitable for use with cardiographs and the like are provided with a resistance 9, which may be 1M#. in the example described,- shunted by a capacity 10 of 1ÁF. and connected in series with the coupling resistance 8 of 0À1 M#. for the purpose of giving the coupling a large time constant. The network 8, 9, 10 is connected to the grid side of the coupling condenser 7 so that anode current does not flow through it. Curve E, Fig. 3, show the gain plotted against frequency when the mesh 9, 10 is omitted, while curves D, F show the effect of the mesh with a large and a small value, respectively, of condenser 10. Thus the device can have a high-pass or a bandpass filtering effect. The low-frequency cutoff can be sharpened by the addition of inductance in parallel with the mesh 9, 10.
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