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Measurement Technique

IP.com Disclosure Number: IPCOM000090628D
Original Publication Date: 1969-Jun-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Antipov, I: AUTHOR

Abstract

The measurement of the complex ratio of (I(C)/I(B)absolute value of (VCB=0) leads to the determination of the base transit time and the emitter time constant for the frequency of measurement when the equation omega Bo r(e)(C(C) + C(E))<< 1 is satisfied. C(D) = diffusion capacitance, C(E)= emitter capacitance, r(e)= emitter resistance, Bo = low-frequency Beta, and omega = 2 pi f. If (I(C)/I(B)) (VCB=0) = A/phi @ omega is satisfied, then Tan phi = omega Bo r(e) (C(E) + C(D)) = omega Bo tau(T) where Bo = A/Cos phi. The drawing shows the technique of obtaining the complex ratio of I (C)/I (B) at a specified condition of VCB=0 and at a desired DC bias condition, using a vector voltmeter.

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Measurement Technique

The measurement of the complex ratio of (I(C)/I(B)absolute value of (VCB=0) leads to the determination of the base transit time and the emitter time constant for the frequency of measurement when the equation omega Bo r(e)(C(C) + C(E))<< 1 is satisfied. C(D) = diffusion capacitance, C(E)= emitter capacitance, r(e)= emitter resistance, Bo = low-frequency Beta, and omega = 2 pi f. If (I(C)/I(B)) (VCB=0) = A/phi @ omega is satisfied, then Tan phi = omega Bo r(e) (C(E) + C(D)) = omega Bo tau(T) where Bo = A/Cos phi. The drawing shows the technique of obtaining the complex ratio of I
(C)/I (B) at a specified condition of VCB=0 and at a desired DC bias condition, using a vector voltmeter. The condition of VCB=0 is obtained by tuning transmission lines L1 and L2 for zero impedance at collector and base terminals by variable capacitors C1 and C2. Having transmission lines L1 and L2 equal in length and in characteristics, V(C)/V(A) = (I(C)/I(B)absolute value of VCB=0). In addition, since F(T) of the transistor at zero collector load is related to tau(T) and is very closely approximated by its inverse f(T) approx. 1/2pi tau(T), measurement of tau(T) also gives a good indication of f(T), with advantage that the measurement is performed at much lower frequency.

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