Resistors

1st number

1st band

carbon film resistor, metal glaze resistor

2 types of fixed resistors

Multiplier /10

Gold (3/4 band)

Tolerance 5%

Gold (last band)

8

Gray band

5

Green band

increases

Resistance of most metals _________ as the temperature increases

type of material, conductors length, cross-sectional area, temperature

Resistivity is determined by...

metal glaze resistor

Resistor made by combining metal with glass, resistance determined by amount of metal in compound

Variable resistors

Resistor that has values that can be changed over a range

limit flow of current, produce a voltage divider

Resistors perform what 2 functions

Multiplier /100

Silver (3/4 band)

Tolerance 10%

Silver (last band)

larger

Smaller the gauge number, _____ the wire

tolerance

last band

2nd number

2nd band

multiplier

3rd band

american wire gauge

AWG stands for...

0

Black band

6

Blue band

1

Brown band

inexpensive, readily available, standard sizes and wattage

Carbon resistors are

Metal film resistors

Constructed by applying a film of metal to a ceramic rod in a vacuum, resistance determined by metal type and thickness

one ohmic value

Fixed resistors only have

smaller

Larger the gauge number, _______ the wire

Carbon, less resistance

More ______ within a resistor means _____ _______

14ga and 12ga

Most prevalent wire sizes in houses

Tolerance 20%

No color (last band)

3

Orange band

2

Red band

resistance

V/I=

Rheostat (light dimmer, ceiling fan)

Variable resistor that varies current

Potentiometer (volume knob)

Variable resistor that varies voltage

7

Violet band

9

White band

fixed resistor

Wire wound resistor made by winding resistive wire around ceramic core, high power rating needed

4

Yellow band

carbon film resistor

ceramic rod coated with a film of carbon, high tolerance rating