Electricity 3: Current and voltage in circuts Flashcards
Define current
Current is the rate of flow of charge (electrons) around a circuit.
How do you measure current?
Current is measured using an ammeter.
An ammeter is always positioned in series.
What is the unit for current?
Current is measured in amps (A).
What happens to current in a series circuit.?
In a series circuit the current is the same at all points.
What happens to current in a parallel circuit?
In a parallel circuit the current is shared between the branches.
Define voltage
Voltage is the energy given to the charge in a circuit. It is supplied by the battery.
How do you measure voltage?
Voltage is measured using a voltmeter. To measure the voltage across a component, a voltmeter is connected in parallel with that component.
What is the unit of voltage?
Voltage is measured in volts (V).
What happens to voltage in a series circuit?
In a series circuit the voltage is shared between the components.
What happens to voltage in a parallel circuit?
In a parallel circuit the voltage across each branch is equal to the supply
Define resistance
Resistance tells us how hard it is for current to flow in a circuit.
How do you measure resistance?
By using an ohm meter
What is the unit for resistance?
Resistance is measured in Ohms (Ω)
What happens to the current in a circuit as the resistance increases?
As the resistance of a circuit increases the current in the circuit decreases.
Describe an electromagnet
When current moves through a wire a small magnetic field is produced. If a wire is coiled around a piece of Iron an electromagnet can be made.
