. Practical wireless telegraphy; a complete text book for students of radio communication . PHONES J Fig. 186—Cascade Connection of Vacuum Valve withOne Lighting Battery. RECEIVING CIRCUITS, DETECTORS, TUNING APPARATUS. 163 144. The Vacuum Valve Amplifier.—The incoming signals made audibleby the simple vacuum valve circuit shown in Fig. 179, may be amplified consider-ably by connecting several oscillation valves in cascade as per the diagram, The fluctuations of current in the local circuit are impressed upon the gridsof a second and third valve where due to the relaying or trigger ac
. Practical wireless telegraphy; a complete text book for students of radio communication . PHONES J Fig. 186—Cascade Connection of Vacuum Valve withOne Lighting Battery. RECEIVING CIRCUITS, DETECTORS, TUNING APPARATUS. 163 144. The Vacuum Valve Amplifier.—The incoming signals made audibleby the simple vacuum valve circuit shown in Fig. 179, may be amplified consider-ably by connecting several oscillation valves in cascade as per the diagram, The fluctuations of current in the local circuit are impressed upon the gridsof a second and third valve where due to the relaying or trigger action of the bulb,progressive amplification is obtained. VALVE Ni. Fig. 187—Circuit for Cascade Ampliiication of Radio Frequencies, In the diagram, Fig. 185, in which the left-hand part of the circuit starts with the sec-ondary winding of the receiving transformer, the telephones are removed from the localbattery circuit and replaced by an iron core inductively coupled transformer of audio-fre-quency dimensions. The primary winding L-1 is connected in series with the battery B-2,but the terminals of the secondary winding L-2 are connected to the grid and filament ofthe second vacuum valve. The circuit continues in this manner throughout several bulbs,but generally the fluctuations of current in the third or fourth step are strong enough toparalyze the valve, particularly if the vacuum is not sufficiently good. Usually thissystem does not function well above the third step. To prevent the accumulations of extrahigh potentials on the grids of the amplifying valves, an extremely high resistance, R (offrom 500,000 to 1,500,000 ohms resistance) may be c
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecttelegra, bookyear1917
