1. U3e-L12
March 31, 2008
DRILL
A 75-watt light bulb is plugged into a wall socket (120V AC).
What is the current going through the light bulb? (Use Joule’s Law)
What is the resistance of the light bulb? (Use Ohm’s Law)
If three light bulbs are in series, what is the total resistance [use the answer from b) above]? Sketch a schematic
If the two lights in series are plugged into a wall outlet, what is the current going through them [use the resistance from c) above]?

2. U3e-L12
DRILL – Solution
A 75-watt light bulb is plugged into a wall socket (120V AC).
What is the current going through the light bulb? (Use Joule’s Law)
P = VI
P = V I I = P/V
I = 75W / 120V
I = .625 A
P = 75 watts
V = 120 volts
I = ? amps

3. U3e-L12
DRILL – Solution
What is the resistance of the light bulb? (Use Ohm’s Law)
V = 120 volts
I = .625 amps
R = ?
V = IR
V = I R R = V / I
R = 120V / .625A
R = 192 Ohms

4. DRILL – Solution R = 192 W + 192 W + 192 W R = 576 W
U3e-L12
DRILL – Solution
If three light bulbs are in series, what is the total resistance [use the answer from b) above]? Sketch a schematic
192 Ohms
R = 192 W W W T
R = 576 W T

5. DRILL – Solution V = 120 volts R = 576 ohms I = ? V = IR
U3e-L12
DRILL – Solution
If the two lights in series are plugged into a wall outlet, what is the current going through them [use the resistance from c) above]?
V = 120 volts
R = 576 ohms
I = ?
V = IR
V = I R I = V / R
I = 120 volts / 576 ohms
I = .208 amps

6. ELECTRIC MOTOR PROJECT
U3e-L12
ELECTRIC MOTOR PROJECT
Monday, Tuesday, Wednesday class time to complete the project
By Friday have an operating motor
Notes:
Test electromagnet before constructing entire motor
All angles must be precise, all parts must be correctly balanced, friction must be MINIMIZED
Locate wires precisely

7. Orthogonal Views of Product SKETCH and LABEL
U3e-L8
Orthogonal Views of Product SKETCH and LABEL
Motor Design, Design Drawings, and Lesson
Courtesy of Fred Nastvogel

8. CUT WITH SCISSORS CUT WITH HACKSAW CUT WITH BAND SAW CUT WITH BAND SAW
U3e-L11
CUT WITH SCISSORS
CUT WITH HACKSAW
CUT WITH BAND SAW
CUT WITH BAND SAW
Motor Design, Design Drawings, and Lesson
Courtesy of Fred Nastvogel

9. Motor Design, Design Drawings, and Lesson Courtesy of Fred Nastvogel

10. Orthogonal Views of Product SKETCH and LABEL
Motor Design, Design Drawings, and Lesson
Courtesy of Fred Nastvogel