ELEC 101, Spring 2005

Prof. Rich Kozick

Prof. Rich Kozick

**Reading:**Please continue to study Chapter 1 in the Bobrow text, and begin reading Chapter 2, Sections 2.1 and 2.2, on nodal analysis.-
A certain bicycle lighting system uses a lamp bulb rated to absorb 20
W of power when it is on. If the system uses four 1.5-V "D" cells
in series (for a total of 6 V) to run the system:
- How much current flows through the lamp bulb when it is on?
- What is the equivalent resistance of the lamp bulb when it is on?

- Please solve the following
problems in Chapter 1 of the Bobrow text.
1.30 (combine series/parallel resistors and use voltage dividers)

1.45 (dependent source) -
Consider the voltage divider circuit shown below, where
R
_{1}= 2000 ohms and R_{2}= 3000 ohms. Please find the current,*i*, the voltage*V*, and the voltage across the 2000 ohm resistor. Be sure to draw the circuit diagram in your solution, and label the polarity of the voltage across the 2000 ohm resistor and the direction for the current,_{2}*i*. -
Consider the voltage divider circuit shown below, where
R
_{sensor}is a thermistor whose resistance is 1000 ohms at room temperature and 5000 ohms at body temperature.- If R
_{1}has value 500 ohms, what is the value of the voltage V_{sensor}at room temperature and at body temperature? What is the difference in V_{sensor}at the two temperatures? - What value for R
_{1}*maximizes*the difference in V_{sensor}at the two temperatures?

- If R
- Design a current divider circuit that will produce a current division ratio of 0.5, so that half of the current flows through each branch. The current divider should draw less than 1 milliwatt (1 mW) of power when the input is a 1 A current source. Explain your reasoning.