Institute Massachusetts of Technology Department of Electrical Engineering and Computer Science 6.002 - Electronic Circuits Fall 2000 Homework #4 Handout F00-024
Issued 9/28/2000 - Due 10/5/2000
Read Chapter 4 except Section 4.4. Exercise 4-1: Exercise 4-2: Problem 4.1: Exercise 4.3, Chapter 4. Exercise 6.5, Chapter 6. The zener diode in the circuit below has the v-i characteristic shown at the right. 7 k vS iS 3 k iD
+
iD vD
-
-4.5 0.6 vD (volts)
a)
For the input voltage vS shown below, indicate the time regions where the diode is ON (conducting a current) and OFF (open circuit). Label the boundaries with numerical values. vS(t) (volts) 20
10 -20
20
30
40
t (ms)
b) For the input voltage vS shown above, sketch the diode voltage waveform, vD(t). Label all breakpoint coordinates with values and units. c) Find the value of the current is for vS = -25.5 volts.
Problem 4.2: Problem 4.3, Chapter 4. Replace the words "piecewise-linear" with "incremental" in parts and c) d), and use as the operating point v = 3, i = 0.
(over)
Problem 4.3:
Consider the circuit containing a nonlinear element N as shown in Figure 4.3. The i-v relation for
v
a ------- the element N is given by i a = (10 A) 1 e 5V .
2 ia + vi -
N
+ va -
a)
Write an equation relating the voltage va to the input voltage vi.
b) Solve for the voltage va for vi = 10 volts. Note: This requires that you solve the equation in part a. itera tively for va. Hint: Use the exponential term to solve for va as a function of va and iterate. c)
a Find the incremental change in va for a 2% increase in vi and calculate the ratio -------- . -
v v i
d) Find the value for the incremental resistance of the nonlinear element N by linearizing the expression for ia about the operating point when vi = 10 volts. e) Draw the incremental circuit for the circuit in Figure 4.3. f)
a Find the ratio -------- from the incremental circuit and compare with your exact value from part c. -
v v i