In a linear two – port network, when 10 V is applied to Port 1, a current of 4 A flows through Port 2 when it is short-circuited. When 5 V is applied to Port, a current of 1.25 A flows through a 1 Ω resistance connected across Port 2. When 3 V is applied to Port 1, then current (in Ampere) through a 2 Ω resistance connected across Port 2 is __________.
Concept:
I1 = Y11V1 + Y12V1 ....1
I2 = Y21V1 + Y22V2 .....2
Where, I1, V1 are input variables and I2, V2 are output variables.
Y11, Y12, Y21, and Y22 are Y matrix elements.
Calculation:
Case 1: When output port is short circuit so V2 = 0 so from eqn 2
4 = 10 Y21 ⇒ Y21 = 0.4
Case 2: Now connect 10 V at input terminal and current flow in output terminal is 1.25 A so from eqn 2
1.25 = (0.4)( 5 ) + 1.25 Y22
⇒ Y22 = -0.6
Now input voltage is 3 V so current through 2 Ω connected in output port is
I2 = 0.4 × 3 – 0.6 (2I2)
= 1.2 – 1.2 I2 = 0.545 AImportant Questions from Two Port Networks
A two-port network is reciprocal if _________
A short-circuit admittance matrix of a two-port network is
\(\left[ {\begin{array}{} 0\\ {\frac{1}{2}} \end{array}\begin{array}{} { - \frac{1}{2}}\\ 0 \end{array}} \right]\)
The two-port network is
A two-port network has scattering parameters given \(\left[ s \right] = \left[ {\begin{array}{*{20}{c}} {{s_{11}}}&{{s_{12}}}\\ {{s_{211}}}&{{s_{22}}} \end{array}} \right]\). If the port 2 of the two-port is short-circuited, the s11 parameter for the resultant one-port network is
With 10 V dc connected at port A, the current drawn by 7 Ω connected at port B is
With 6 V dc connected at port A, 1 Ω connected at port B draws 7/3 A. If 8 V dc is connected to port A, the open circuit voltage at port B is
