Electrical news and engineering . oltage anywhere to times, let us say six times. What is meant by thisis that if we put a voltage on the grid, the current in theplate circuit increases by six times as much as if we hadadded that much voltage in the plate circuit itself. Supposefor instance a battery of 1-1/2 volts be applied to the grid itwill boost the plate current as much as six times 1-1/2 ornine volts added to the plate circuit. The current in theplate circuit is also amplified so that the power amplifica-tion of the peanut tube is 187, which means that thestrength of a signa
Electrical news and engineering . oltage anywhere to times, let us say six times. What is meant by thisis that if we put a voltage on the grid, the current in theplate circuit increases by six times as much as if we hadadded that much voltage in the plate circuit itself. Supposefor instance a battery of 1-1/2 volts be applied to the grid itwill boost the plate current as much as six times 1-1/2 ornine volts added to the plate circuit. The current in theplate circuit is also amplified so that the power amplifica-tion of the peanut tube is 187, which means that thestrength of a signal is amplified 187 times as was previouslystated. Why the Peanut Tube is a Good Detector1 would like to explain very ibriefly how it is that thistube which is essentially an amplifying tube is such a gooddetector, because you will realize the great advantage ofstandardizing on one type of tube provided it is capable ofdoing both jobs well. Many detector tubes as you knowhave a little hump in their characteristic curves. With such. Fig. 1—Theoretical voltage tubes sharp detection is obtained, but it is necessary to ad-just the plate voltage so that the detection takes place onthe hump of the curve. Such a hump on the curve rendersthe tube useless as an amplifier. The peanut tube has nosuch hump in its characteristic curve, and does not needany, because a different principle is used to accomplish de-tection. In order to explain this, let us consider a tube inwhich there is no grid and no plate battery. This you willremember is similar to the so-called Edison effect, al- ready mentioned at the beginning of this paper. Edisonplaced a plate within the bulb of his incandescent lamp andconnecting this plate with the positive end of the filamenthe was al)!e to obtai:i several milliamperes of current. Thiswas afterwards found to be due to electrons or particles ofnegative electricity (lowing through the vacuous space ofthe lamp from the filament to the plate, and it is the con-trol of
Size: 1698px × 1471px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bo, bookcentury1800, bookdecade1890, bookidelectricalnewsen31donm
