Hybrid Parameters (MA096E)

The hybrid parameters were developed by transistor manufacturers to indicate the values of their internal elements. Using hybrid parameters calculations involving transistor circuits can made easier. Figure bellow shows the equivalent circuit for such hybrid parameters.

 

Definitions:

The hybrid parameters in the circuit shown above are defined as follows:

h₁₁ input impedance with short-circuit output

h₁₂ reverse open-circuit voltage amplification factor

h₂₁ forward short-circuit current amplification factor

h₂₂ output admittance with open-circuit input

Formula 1

Input impedance:

h₁₁ = V₁ / I₁ para V₂ = 0

Formula 2

Reverse open-circuit voltage amplification factor:

h₁₂ = V₁ / V₂ para I₁ = 0

Formula 3

Forward short-circuit current amplification factor (?)

h₂₁ = I₂ / I₁ para V₂ = 0

Formula 4

Output admittance:

h₂₂ = I₂ / V₂ para I₁ = 0

Where:

V₁ is the input voltage in volts (V)

V₂ is the output voltage in volts (V)

I₁ is the input current in amperes (A)

I₂ is the output current in amperes (A)

Derivated formulas:

Formula 5

Input voltage:

V₁ = h₁₁ x I₁ + h₁₂ x V₂

Formula 6

Output current:

I₂ = h₂₁ x I₁ + h₂₂ x V₂

Formula 7

Determinant h:

det h = h₁₁ x h₂₂ - h₁₂ x h₂₁

Where: det h is the determinant formed by the hybrid parameters as follows:

det h = 

TABLE - Letter Symbols and Abbreviations for Transistors