ELEC 101
Prof. Rich Kozick
Spring, 1998

Homework 7

Date Assigned: Monday, February 23, 1998
Date Due: Friday, February 27, 1998

Note: This HTML file is incomplete since the circuit diagrams are not included. Please get a paper copy of the assignment.

1.
Suppose you have a real (non-ideal) voltage source with 10 ohm internal resistance, as shown below. The source is used to light a bulb, as shown.
(a)
What value of resistance should the bulb have in order for it to shine as brightly as possible?
(b)
How much power is dissipated by the bulb when its resistance has the value you specified in part (a)?

(c)
How much power is dissipated by the bulb when it has resistance 1 ohm? What about 100 ohm?

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2.

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3.
The voltage divider shown in circuit (A) below has been used to convert an ideal 10 volt source into a 5 volt source. Please find the Thevenin model for circuit (A). That is, find voc and R0 in circuit (B) so that both circuits have the same voltage and current behavior at their terminals.

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4.
Suppose that a voltage source (also called a power supply) is to be designed such that it provides 12 volts when its terminals are open-circuited (nothing connected between them). In addition, the voltage source must be able to provide at least 70 watts of power to a load. What is the maximum value of R0 in the Thevenin model for this source?

(The load resistance RL can be assumed to be matched to R0 for maximum power transfer.)

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