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Common Transistor Amplifier and Bias Supply

IP.com Disclosure Number: IPCOM000052409D
Original Publication Date: 1981-Jun-01
Included in the Prior Art Database: 2005-Feb-11

Publishing Venue

IBM

Related People

Authors:
Schwarz, TA [+details]

Abstract

For transducers such as thermocouples or strain gages, the common base amplifier provides termination and amplified voltage output, eo. The input signal, is, is produced by the DeltaR, the change in the source resistance Rs, which modulates the current through itself. The quiescent current, Is, (see original) is = V(B)/R(S) and eo = is x R(L), eo is constrained R(L)I(S)<(V-V(B) ) for linearity. If DeltaR is a small percentage of R(S), is<< I(S) and eo is small. By adding a DC augmentation current, I(CA), R(L) I(L) = R( (I(s)-I(A) and R(LA) I(LA) = R(L)I(L) => R(LA) = R(L) I(S)/(I(S)-I(A))>> R(L), where the only constraint is I(A) < I(S) - is(max). Since is (max) is fixed by V(B)/Delta R, eo(A) = is R(LA) = is times R(L) times I(s)/(I(s)-I(A))>>