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
