. Bell telephone magazine . t filamentfrees electrons and if a battery, B, isconnected between the filament and aplate, P, inside an evacuated space insuch a way that the plate will bepositively charged with respect to thefilament, then the free electronswill be attracted toward the plate andcross through the vacuum space tostrike the plate. This is a flow ofelectric current and is shown by thecurrent indicator, I. However, if thevacuum is not perfect there will besome residual gas molecules andatoms floating around in it. Theseare relatively very heavy in compari-son with the free electron, a
. Bell telephone magazine . t filamentfrees electrons and if a battery, B, isconnected between the filament and aplate, P, inside an evacuated space insuch a way that the plate will bepositively charged with respect to thefilament, then the free electronswill be attracted toward the plate andcross through the vacuum space tostrike the plate. This is a flow ofelectric current and is shown by thecurrent indicator, I. However, if thevacuum is not perfect there will besome residual gas molecules andatoms floating around in it. Theseare relatively very heavy in compari-son with the free electron, and shouldsuch a molecule or atom happen toget in the line of flight of the elec-tron a collision will occur, and the electron may bounce off it, combinewith it, or discharge more electronsby overcoming the forces which bindthem within the atom. Today, thanks to Arnold, we knowthat the way to obviate such colli-sions is to reduce the possible sourcesof interference, and the liberation offree electrons in high vacua is funda-. IINDICATOR BBATTERY A BATTERY Fig, I. A diagrammatic representation of the elementary principles of the vacuum tube mental to electronics—since underthat condition the occurrence of colli-sions with residual gas atoms andmolecules is reduced to the minimum. Handing On the Torch Many scientists before and sinceArnold have contributed to todays 176 Bell Telephone Magazine AUTUMN knowledge of free electrons and howto produce, control, and utilize them. In 1883 Thomas A. Edison wasexperimenting with the incandescentelectric lamp. He had used in theprocess of manufacture of the carbonfilament a third wire sealed throughinto the partially evacuated filament was heated by directcurrent and he observed that if ameter was connected between thisthird wire and the positive end ofthe filament a current would flowthrough the meter while if connectedto the negative end of the filamentno current would flow. This phe-nomenon came to be known as theEdison Effect
Size: 1589px × 1572px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthoramerican, bookcentury1900, bookdecade1920, bookyear1922
