Transistor Basics is a free introductory textbook on transistors and their basic applications. See the editorial for more information....

Resistance Parameters in Terms of Hybrid Parameters

Author: Leonard Krugman

The relationship between the r and h values can be determined by straightforward substitution and the simultaneous solution of equations 7-1 and 7-2, as follows:

A. transistor_basics_07-38.gif when i2 = 0. Under this condition

Ci = h11ix + h12e2 Eq. (7-1A)
0 = h21i1 + h22e2 Eq. (7-2 A)

If these are solved simultaneously,

and therefore


Eq. (7-3)

B. transistor_basics_07-41.gif when i2 = 0. Under this condition equation 7-2A still

applies and is solved

transistor_basics_07-42.gif Eq. (7-4)

C. transistor_basics_07-43.gif when i1 = 0. Under this condition

e1 = h12e2 Eq. (7-1B)
i2 = H22e2 Eq. (7-2B)

If these are solved simultaneously

transistor_basics_07-44.gif and transistor_basics_07-45.gif Eq. (7-5)

D. transistor_basics_07-46.gif when i1 = 0. For this relationship equation 7-2B still

applies and is solved

transistor_basics_07-47.gif and transistor_basics_07-48.gif Eq. (7-6)

E. The current gain transistor_basics_07-49.gif

As a numerical example of these conversions, the manufacturer's rating sheet for the G.E. type 2N45 specifies the following typical values for the hybrid parameters: hn = 40 ohms, h12 = 2.5 x 10-4, h21 = - .92, h22 = 1.0 x 10-6 mhos.



Last Update: 2007-07-12