EXPERIMENT # II

Department of Electronics and communication Engineering

L A B O R A T O R Y M A N U A L

f o r

C I R C U I T S & N E T W O R K

( E C- 3 9 1 )

Department

of

Electronics and Communication Engineering

EM-4/1, Sector V, Salt Lake

Kolkata-700 091

EXPERIMENT # 3 TITLEDetermination of impedance (Z) parameters and admitance (Y) parameters of two port network using PSpice. OBJECTIVE

1)To determine the open circuit impedance parameters of the T network as shown in the figure below using PSPICE simulation.

Fig:1

2)To determine the short circuit admittance parameters of the network as shown in the figure below using PSPICE simulation.

Fig.2

THEORY :

IMPEDANCE (Z) PARAMETERS:

Let us consider a linear passive two port network as shown in figure below:

We know, V1= Z11 I1 + Z12 I2 (1)

V2= Z21 I1 + Z22 I2 (2)

Z-parameters are obtained by making either terminals 11 open circuited or terminals 22 open circuited.

is called the input impedance or driving point impedance with output open circuited.

is called the forward transfer impedance with output open circuited.

is called the reverse transfer impedance with output open circuited.

is called the output impedance with input open circuited.

ADMITTANCE (Y) PARAMETERS

Let us consider a linear passive two port network as shown in figure below:

The Y-parameters of this network can be obtained by expressing I1 and I2 in terms of V1 and V2.

I1= Y11 V1 + Y12 V2 (1)

I2= Y21 V1 + Y22 V2 (2)

Y-parameters are obtained by making either terminals 11 short circuited or terminals 22 short circuited.

is called the input admittance or driving point admittance with output short circuited.

is called the forward transfer admittance with output short circuited.

is called the reverse transfer admittance with input short circuited.

is called the output admittance with input short circuited.

PROCEDURE

Determination of Z11 & Z21 Referring to the T-network above, the steps are -

a) o/p port to be kept open ( i.e. I2=0)

b) voltageto be applied at the i/p port (i.e. V1=10V)

c) o/p port voltage (i.e. V) to be measured

d) i/p port current (i.e. I) to be measured

Determination of Z12& Z22

Referring to the T-network above, the steps are --

a) i/p port to be kept open ( i.e. I1=0)

b) voltageto be applied at the o/p port (i.e. V2=15V)

c) i/p port voltage (i.e. V) to be measured

d) o/p port current (i.e. I) to be measured

Determination of Y11 & Y21 Referring to the T-network above, the steps are --

a) o/p port to be kept shorted thru an ammeter ( i.e. V2=0)

b) voltage (say 2