# How to draw the small signal equivalent model of a circuit

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#### anandmakate

##### Newbie level 6
Hello everyone,
Could you please tell me how to draw the small signal equivalent ofa given mos circuit.Please give me at least the link which provides me the complete guidance regarding it. Any help is greatly appreciated.

Thanks

#### Electronica

##### Full Member level 2
cosider either the pi or t diagram of a device

#### anandmakate

##### Newbie level 6
Re: How to draw the small signal equivalent model of a circu

oh ..thanks for the valuable reply....could you please illustrate with an example...

#### kiprono

Re: How to draw the small signal equivalent model of a circu

In a two-terminal network, the terminal voltage is related to the terminal current by the impedance Z =V/I. In a four-terminal network, if each terminal pair (or port) is connected separately to another circuit as in Fig. 1, the four variables i1, i2, v1, and v2 are related by two equations called the terminal characteristics. These two equations, plus the terminal characteristics of the connected circuits, provide
the necessary and sufficient number of equations to solve for the four variables.

The terminal characteristics of a two-port network, having linear elements and dependent sources, may be written in the s-domain using z-parameters as shown in eqt. (1).

The coefficients Zij have the dimension of impedance and are called the Z-parameters of the network. The Z-parameters are also called open-circuit impedance parameters since they may be measured at one terminal while the other terminal is open. They are given in eqt. (2)

#### kiprono

Re: How to draw the small signal equivalent model of a circu

h-parameters
Some two-port circuits or electronic devices are best characterized by the terminal equations in eqt. (3), where the hij coefficients are called the hybrid parameters, or h-parameters.
Fig.2 shows a simple model of a bipolar junction transistor in its linear region of operation. By inspection, the terminal characteristics of Fig. 2 are given in eqt. (4).
By comparing (3) and (4) gives eqt. (5).

#### Naveed Alam

##### Full Member level 5
Re: How to draw the small signal equivalent model of a circu

any electronic circuit book will teach u this.
PI, HYBRID are used mainly.

Naveed

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