. The Bell System technical journal . t the slopeagain becomes zero or nearly so. There are also two further observa-tions. First, the collector ^oltage is reduced to a verj- small value andsecond, that the critical emitter current is related to the collectorcurrent. From the small-signal relation, Vc = R21L + RoJc (2) or Vc = R220CU + R22IC, (3) * It is tacitly assumed that in the relation y = f(x) that there are extremes atwhich rj becomes essentially constant and independent of further change in theindependent variable x. The point farthest removed from the origin at which thedependent vari
. The Bell System technical journal . t the slopeagain becomes zero or nearly so. There are also two further observa-tions. First, the collector ^oltage is reduced to a verj- small value andsecond, that the critical emitter current is related to the collectorcurrent. From the small-signal relation, Vc = R21L + RoJc (2) or Vc = R220CU + R22IC, (3) * It is tacitly assumed that in the relation y = f(x) that there are extremes atwhich rj becomes essentially constant and independent of further change in theindependent variable x. The point farthest removed from the origin at which thedependent variable becomes constant is termed saturation. The point closest tothe origin at which the dependent variable becomes constant is termed cutoff. 1224 THE BELL SYSTEM TECHNICAL JOURNAL, NOVEMBER 1952 11 w V A V \ w \ i\ i\ \ N \ 1 W \\ A s \, i\i A \ \ ^ ^ w V \V \ \ \\ \ \ ^ d\ \ \ \ \ \ \ V II \ >—1 o <tlj IIiu<o 1(. c *^ ■ ■ ^ 1 o II w 1—1 k ^ ^^ 1 q L ^ q i V o » (J o^3 < (0 Io k m V q~ \ 5- ^ UJ -*^ n ^. FORWARD CHARACTERISTIC SLOPE = Rg, i K ^^ « 1 \> ^^ r- o t ^ ■^ 1— o s -^ ^ .,,__l q ^«~. ^ o k ^ -^ ■ d 1II d -1 q -T qrvi1 IIo - . 30VnOA a3iillM3 33ViioA aoioanoD TRANSISTORS SWITCHIXG CIRCUITS 1225 the critical emitter current for collector \oltaj2;e cut oft may be obtainedby setting Vc = 0, as, /. = -- (4) a This relationship is dual to th(> gild \()ltage-plate voltage relation intubes for plate current cutoff as, 1^ = —(Vp/^l). The criteria, for de-fining the three regions are thus established as: Region I (Collector \oltage Saturation): /, < 0 (;)) Region II (Active): 0 < I, -- (7) a The identification of de\ice parameters will be made for the severalregions by a single prime for Region I as i\ , none for Region 11 as 7\ ,and three primes for Region III as i\ . LIXEARIZATIOX OF THE CHARACTERISTICS AND APPROXIMATIONS The next step is to linearize the characteristics and to make suitableapprox
Size: 1271px × 1965px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
