M3.7 Flashcards
What is resistance?
The obstruction of the electron flow caused by a certain material
What is the specific resistance?
This relates to the type of material used
What is needed to work out resistance of a wire?
The length of the wire and the cross-sectional area
What affects the resistance?
- specific resistance
- length
- Ross-sectional area
What are the main four bands on a resister for?
They indicate the amount of resistance a resister gives.
- Band
- Band
- Multiplier
- Tolerance
E.g 2,9,x10K,-+1%
What uses the same colour code system as resisters?
Capacitors
What is a potentiometer?
Is a variable resistor
What is a rheostat?
It’s a resistor that has to be set to your specific value and not to be touched anymore
What is a Wheatstone bridge?
It is a electrical scale that helps you compare the resistance of two resistors.
Can also help find an unknown resistance of a resistor
What does NTC and PTC staff for?
Negative and positive temperature coefficient
What is a NTC resister?
Their resistance decreases as the temperature increases
What is a PTC resister?
Their resistance increases as the temperature increases
What does a Voltage-Dependent resistors (VDR - Varistor) do?
As the voltage increase the resistance decreases
What would you do to work work out total resistance and total voltage in a series circuit?
Add them all together to get the total
