ECE20B, Spring 2001. Final Exam lab questions.
- (15 pts. total) For the op-amp circuit with a resistive divider in the output network shown in Fig. 1 answer the following questions:
a) (4 points) What is the input (Vin/Iin) impedance of the circuit in Fig. 1? What is the input impedance of an ideal op-amp?
b) (5 points) What is the output impedance (Vout/Iout) of the circuit in Fig. 1?
c) (5 points) Write out the expression for Vout/Vin in terms of Rs, Rf, R1 and R2.
d) (1 point) Obtain numerical value of expression for Vout/Vin if Rs = 1kW, Rf = 5kW, R1 = R2 = 10kW.
Figure 1.
- (10 pts. total) For two circuits shown in Fig. 2 a) and b) draw the timing diagrams and explain the purpose of each circuit. The switching point of the NAND gate is 2.5V and Z point is initially at 5V.
Figure 2.
- (15 pts. total) For the D flip flops circuit shown in Fig. 3 answer the following questions (note that the first flip flop is positive edge-triggered, but the second one is negative edge-triggered):
a) (5 points) Fill up the truth table for the output ports X, Y, V and W as a function of input ports A and Clock. Assume that the initial state of the input port A when clock goes up is either 1 or 0.
Clock / A / X / Y / V / W↑ / 1
↑ / 0
b) (10 points) Complete the timing diagram for this circuit. The initial states of D flip flops and input waveforms are shown in Fig 3.
Figure 3.
- (10 pts. total) Programming of the robot:
a) (4 points) Describe what should you do to program reset counter command. How can you reset counter manually? How can you program the pause command?
b) (3 points) Suppose that you entered 120 commands in the memory. Estimate how long this program will execute if you set the clock frequency to 2Hz, to 4Hz?
c) (2 points) How many commands does the robot have?
d) (1 point) What is the maximum number of command combinations in the robot with four memory lines?
Final Exam lab questions ECE20B 3/3