Resistors Flashcards
What are the 2 types of resistors?
Fixed and variable
What are the 4 types of fixed resistors?
Carbon film, Metal film, Wire wound, Thick film
Which fixed resistor is used in high power applications?
Wire wound
Characteristics of carbon film resistors
Low power, 1ohm to 10Mohms, typical tolerance of 5%, tan colour
Characteristics of metal film resistors
Low power apps, greater range than carbon film, typical tolerance of 1%, blue colour
Characteristics of wire wound resistors
High power apps, low ohmic range, typical tolerance 10%, rectangular ceramic casing (white box)
Characteristics of thick film resistors
Low power apps, very small, typical tolerance 5%, small size no legs
What are the 3 types of variable resistors?
Potentiometers, Light Dependant Resistor (LDR), Thermistors
What are the 2 types of Potentiometers?
Linear and rotary
Application of potentiometers
Fuel measuring system
Describe potentiometer functions
3 terminals
Can be used as a rheostat if 2 terminals are used
Can be used as a variable voltage divider if 3 terminals are used
Resistance varied by rotary or linear motion
Characteristics of LDRs
2 terminals
Low resistance in bright light
high resistance in low light
Resistance change is non-linear
Application of LDRs
Used in display backlighting -> when night time, high resistance so dim
Characteristics of thermistors
2 terminals
PTC - resistance is proportional to temperature
NTC - inversely proportional
Resistance change is non-linear
Application of thermistors
Used in temperature monitoring and regulating applications i.e. cockpit heating system in aircraft
