The Hybrid-pi Model: Some Discrepencies and the Suggested Universal Model

Abstract

Certain inconsistencies in the results worked out by Millman and Halkias in his book “Integrated Electronics” impelled the first author to introduce the Universal Hybrid-pi model which incorporates the current generator β₀ i_b in place ofg_m v_π at midfrequencies. The physical reasoning for doing so was the simple argument that why should not the total base nodal current i_b be the useful transistor instead ofi_π. The Universal Hybrid-pi model was found to predict more realistic and practically verifiable performance parameters such as the reverse transmission parameter and the output impedance R₀ of CB configuration. By examining the data sheets of CE h parameters also, the trend in support of Universal Hybrid-pi model seems to be found. Some more accurate and sensitive measurements are in order before the Universal Hybrid-pi model can conclusively be validated.

Indexing terms:

• Device modelling
• Reverse transmission
• Non-unilaterality