Circuits Flashcards
What is voltage
Voltage is the driving force that pushes the current round
What is resistance
Resistance is anything In the circuit which slows the flow down
What happens if you increase the voltage
More current will flow
What happens if you increase the resistance
Then less current will flow
What does the ammeter measure
Measures the current( in amps) flowing through the component.
It must be places in series, it can be put anywhere in series in the main circuit, but never in parallel like voltmeter
What does voltmeter measure
Measures the voltage ( in volts) across the component.
Must be placed in parallel around the component- not around the variable resistor or battery!
What is the very basic circuit used for
Testing components
What is found In series
The component, ammeter and the variable resistor. They can be placed in any order in the main circuit.
What happens as you vary the variable resistor
As you very the variable resistor it alters current flow through the circuit.
This allows you take readings from the ammeter and voltmeter, which can be used topknot V-I graphs
What is the equation for calculating resistance
Resistance= potential difference/ current
What are variable resistors and what do they do
A resistor whose resistance can be changed by twiddling a knob or something
They’re great for altering current flow.
What does a diode do
It lets current flow freely through it in one direction but not in the other
What is a light- dependent resistor( LDR)
In bright light, the resistance falls
In darkness, the resistance is highest
This makes it a useful device for various electronic circuits, e.g. Automatic night lights, burglar detectors
What happens with a thermistor
In hot conditions, the resistance drops
In cool conditions, the resistance goes up
Thermistors make useful temperature detectors
What is current
Current is the flow of electrons around the circuit. Current will only flow through a component if there is a voltage across the component
