Current, Voltage, Resistance Flashcards
What is an ammeter used for?
To measure the current: connected in series.
What is a voltmeter used for?
Used to measure the voltage: voltmeter is connected in parallel across a component.
What makes the current bigger?
The larger the voltage of the battery in a circuit.
How is the voltage across a power supply/station measured in?
Across supply: measure of how much energy is supplied to the current
Across component: measure of how much energy is transferred in the components.
How do you work out power?
Power(W) = voltage(V) x current(A).
What does a voltmeter measure?
The difference in energy between the terminals of a battery or bulb.
What is the potential difference (p.d.)?
The difference in energy per unit charge.
What does a potential difference of 1 volt mean to 1 joule of energy?
That is transferred into or out of electrical form for each unit of charge.
What does the more resistance in a circuit mean?
The lower the current.
What has some resistance flow to them?
All electrical components.
What makes the current larger?
The greater the voltage across a resistor.
What is resistance?
A measure of how much a conductor opposes the current.
What is a variable resistor?
A device that allows you to control the current by changing the amount of resistance in a wire circuit.
How to work out the resistance:
Resistance(ohms) = voltage (V)/current(I)
What does a graph of voltage against current will give a straight line through the origin mean?
The current through a fixed resistor is directly proportional to the voltage across it (at constant temperature)
