ECE 250 Homework #5
Due 4/19/04
Problem 1:
a) Visit ON Semiconductor’s web site (www.onsemi.com) and obtain the following information:
• a datasheet for an MUR210 switchmode diode. On the datasheet, find and circle the value for the diode reverse
recovery time. Turn in this datasheet with your homework.
• A PSpice model for the MUR210. Print out this model and turn it in with your homework.
b) Using the MUR210 diode model obtained in part (a), run a PSpice simulation to view the switching speed of this diode.
Use a similar simulation to the one shown in class for the MUR420. You may need to change the frequency of the input
waveform a bit. Use a part called DBREAK in your simulation for the diode. See section 7.F.1 of the PSpice manual for an
example of using the model you obtained.
Problem 2:
For the circuit below:
a) For what values of the load is the output voltage of the circuit constant?
b) For the range of load values found in part (a), what is the maximum power absorbed by the Zener?
c) For the range of load values found in part (a), what is the maximum power absorbed by Rs?
Vout
+
Load
Vzk=5V
D1
+
Rs
180
+
-
V1
12V
Problem 3:
We wish to drive a buzzer from the output of a TTL gate using the circuit below. The buzzer requires 50 mA to operate.
a) Find the value of the base resistor (Rb) needed to make the circuit below work for all possible outputs of the TTL gate.
Assume β=100 and that the output voltage of the TTL gate is between 3.5 V and 5 V.
b) For your choice of Rb from part (a), what is the largest amount of current the TTL gate must supply?
+5
U1A
7400
1
23Q1
Q2N3904
+
Rb
BUZZER
Problem 4:
Vo
-
+
R1
1k
D1
D1N4734A
D2
D1N4734A
-
+
Vin
FREQUENCY = 100
AMPLITUDE = 15
+
a) Plot Vo(t) and Vin (t) by hand.
b) Plot the transfer curve Vo versus Vin by hand.
c) Use PSpice to plot Vo(t) and Vin(t). See section 6.F of the PSpice manual for an example.
d) Use PSpice to plot the transfer curve. See section 6.F.1 of the PSpice manual for an example.
