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Impedance Matching in the Grounded Emitter Connection

Author: Leonard Krugman

As in the analysis of the grounded base connection in Chapter 3, the stability factor transistor_basics_04-29.gif must be less than unity for short-circuit stability. The numerical value of δ for the typical point-contact transistor is transistor_basics_04-30.gif.

This re-emphasizes the fact that the point-contact transistor in the grounded emitter connection is unstable when the output is short-circuited. The stability factor for the junction transistor is transistor_basics_04-34.gif, which confirms the fact that the junction transistor is short-circuit stable in the grounded emitter connection.

The input image resistance is defined in equation 3-37 as: r1 = transistor_basics_04-35.gif . The input image resistance of the point-contact transistor is numerically equal totransistor_basics_04-36.gif. Since the quantity under the square root sign is negative, r1 is imaginary and cannot be built into conventional signal sources. For the typical junction transistor, r1 istransistor_basics_04-37.gif.

The output image resistance defined by equation 3-41 as r2 = transistor_basics_04-38.gif also is imaginary for the Doint-contact transistor. For the junction transistor, r2 is transistor_basics_04-39.gif

Last Update: 2010-11-17