Ohmic/non-ohmic types of resistors Flashcards
What is Ohm’s law?
The current through a component is directly proportional to the potential difference across it as long as the temperature does not change
Name the 2 non-ohmic components?
Filament bulb and diode
In ohmic components, which two variables are directly proportional?
Current and potential difference
If current and potential difference are directly proportional, what does this tell us about the resistance?
It is constant (gradient on I-V graph).
What is an ohmic conductor?
Electrical component where current and voltage are DIRECTLY PROPORTIONAL
What is a non-ohmic conductor?
Electrical component where current and voltage are NOT directly proportional
Name 4 non-ohmic conductors
Filament bulb, diodes, Thermistors, LDRs
Why are filament bulbs non-ohmic?
Because as current increases, · the temperature of the filament increases,
· the ions have more kinetic energy, causing more collisions with electrons
· so the resistance increases
What does LED stand for?
Light Emitting Diode
What does LDR stand for?
Light Dependent Resistor
What is a Diode?
A component that allows current to flow in one direction
Describe the relationship between current and potential difference for a diode.
Current only flows in one direction (has a very high resistance in the other direction)
What happens to the resistance of an LDR as the light intensity increases?
It decreases
What happens to the resistance of a thermistor as the temperature increases?
It decreases
What is an alternating current?
A current that changes direction regularly
