Current, potential difference and resistance Flashcards
What is current and what is it carried by
1) a flow of charge
2) electrons
How can the rate of charge flow (current) be calculated
Charge
———— = current
Time
How does a diode limit the flow of a circuit
It only allows current to flow in one direction
What is the purpose of a fuse in a circuit
To melt/break the circuit if current higher than certain amount
How does one calculate potential difference across a singular component
Energy transferred
—————————— = potential difference
Charge
How are ammeters always connected
In a series with the component
How are voltmeters always connected
In parallel with the component
What is an ohmic conductor
A component of which its current potential graph shows both values to be directly proportional
What is the only occasion where ohms law will come into effect
With a resistor at a constant temperature
What is the correlation between the resistance of the component and the steepness of the current-potential difference graph
The higher the resistance of the component, the less steep the graph will be
How does a diode work
Low forward resistance but high backwards resistance
What happens to the resistance of a thermistor as the temperature increases
It decreases
What happens to the resistance of a filament lamp as the current increases and why
1) It increases
2) Resistance of the filament increases as temp does
What effect does reversing PD have on the shape of the current-potential difference graph
None
On a current-potential difference graph, is current placed on the x-axis or the y-axis
It can be on either (remember this during exam)
