12/1/09 9:14 AM

S4. Physics: Laboratory Problem: (Phys: 17)Current Electricity: Resistors (1)

1. Review: Series and Parallel Circuits

a. Series Circuits: voltage is divided acrosscircuit parts.

b. Parallel Circuits: circuit parts are connectedindependently to the power source.

2. Resistors oppose or ‘resist’ the flow of electrons(current) in a circuit.

a. Resistors come in many forms.

12/1/09 9:14 AM

1. Wirewound / Power resistors.

2. Foil, thin film, and carbon. b. Resistance is measured in Ohms (Ω).

1. The resistance is printed on wirewound andpower resistors.

2. On foil, thin film, and carbon resistors theresistance is given in a color code.

12/1/09 9:14 AM

c. The resistor color code has four color bands.

1. The first and second color bands representnumbers.

2. The third color band is a multiplier.(Add this number of zeros after the first two numbers.)

Brown = 1 Black = 0 Red = 210 + 2 Zeros = 1000 Ω

12/1/09 9:14 AM

3. The fourth color band represents resistor tolerance.

a. Gold band - the total resistance will not varymore than 5%.

b. Silver band - the total resistance will not varymore than 10%.

3. Laboratory Problem: Decoding Resistorsa. Copy the Resistor Color Code into classroom notebook.

b. Draw the matching color band next to each value withcolor pencils.

c. Using the resistor color code determine the values of 10 unknown resistors.

12/1/09 9:14 AM

Resistor Color Code

Black = 0Brown = 1Red = 2Orange = 3Yellow = 4

Green = 5Blue = 6Violet = 7Gray = 8White = 9

Bk

Br

R

Or

Y

G

Bl

V

Gy

W

12/1/09 9:14 AM

33 Ω

47 Ω

360 Ω

100 Ω

27 Ω

Decode thefollowingresistors…

12/1/09 9:14 AM

Decode thefollowingresistors…

560,000 Ω

10,000 Ω

120,000 Ω

220,000 Ω

330,000 Ω

12/1/09 9:14 AM

12/1/09 9:14 AM

Resistor Color ResistanceNumber Bands Ohms (Ω)

1 2 3 4 5

10