In The Name Of God
Sharif University of Technology
Department of Computer Engineering
Electrical Circuit – CE 121
Spring 2005 (1384)
Homework Assignment 5
Instructor: Ahmad Khonsari, Ph.D.
Issued: 83/3/3 - Due: 84/3/9 in class (12-13:30)
1) Determine the input resistance seen from AB port (figure 1).
(Answer: Rin = −
R1 R3
)
R2
Figure 1
2) Consider the circuit shown in figure 2. Show that it acts as a Voltage Controlled Current Source
(abbreviated VCCS).
Hint: It is sufficient to prove that iout = k vin .
Figure 2
1
3) Determine the output voltage of each Op-Amp for the circuit shown in figure 3.
Figure 3
4) Consider the circuit shown below (Fig. 4). Determine the output voltage ix for t > 0. The switch is
assumed to be closed for t > 2.
Figure 4
5) Consider the circuit shown in figure 5. The switch is assumed to be closed for long time.
Determine vo(t) for every t.
Hint: As I stated earlier in the class, the current of equivalent inductor at t=0+ should be
determined using this principle that magnetic flux is conservative. It is the dual one of
electrical charge.
2
Figure 5
6) Find the following quantities for the circuit shown in figure 6.
i L (0 + ) , vC (0 + ) , i L (∞) , vC (∞) ,
( )
( )
dvC + diL +
0 ,
0
dt
dt
Figure 6
Good Luck.
Mohammad Sadegh Talebi.
3