Chapter 4 🚨 Flashcards
(60 cards)
Do you use ammeters in series or in parallel?
Series
In a parallel circuit, how do you calculate the total current?
The total current is the sum or the currents in the separate sections
In a parallel circuit what is important to remember about the potential difference across each component?
It is the same
In a parallel circuit, bigger the resistance…
The smaller the current
How to calculate current using potential difference and resistance?
Current = potential difference/ resistance
When you add more resistors in a parallel circuit, why does the total resistance decrease?
The total potential difference is the same, so the total current increases. The total resistance = pd/current, so this means the resistance is less
In a series circuit, what is important to remember about the current?
The current passing through each component is the same
How do you calculate the total potential difference of a series circuit?
Add up the potential differences of all the components
How to calculate the total potential difference of cells in a series circuit
Add up the potential difference of each cell
How to find the total resistance in a series circuit?
Add up the resistance of each component
When you add more resistors in a series circuit, why does the overall resistance increase?
The total potential difference is shared across more resistors, giving each one less. This means that the current decreases, and as the total pd doesn’t change, this means that the total resistance is greater than before
How to calculate resistance using pd and current
Resistance = pd/current
What is a diode?
A non ohmic conductor
Only lets current flow in one direction
What is a light emitting diode?
Emits light when current flows through it in a forward direction
What is a thermistor?
Temperature dependent resistor
Resistance decreases when temperature increases
Why are ammeters connected in series?
So the current across them and the component is the same
Is a voltmeter wired in parallel or series?
Parallel
Why is a voltmeter connected in parallel?
So it measures the potential difference across it
What is resistance?
Resistance is when the electrons travelling around the circuit have go push through the ions in the metal filament
How to calculate resistance using potential difference and current
Resistance (ohms) = potential difference/current
What is the current through a resistor directly proportional to?
The potential difference across the resistor
What is Ohm’s law?
The current through a resistor at constant temperature is directly proportional to the potential difference
Function of cell
Pushes electrons around a complete circuit
Function of switch
Enables current to be turned on and off