P5 - Electric Circuits Flashcards
What is electric current? How does this work?
This is a flow of charge. In an electrical circuit the conductors are full of charges (electrons), which are free to move, so charge can flow in conductors.
Why can’t current flow in insulators such as plastics?
There are few charges free to move.
The loop between each side of a circuit is…
Continuous.
How does a circuit work? Mention charges..
A battery pushes free charges through the wires and these flow all the way round. They are not used up and don’t disappear.
What does current(I) need to flow?
A voltage - driving force - across the component.
What are the units for current?
Amperes - amps.
What is the voltage ? What are its units ?
What is the resistance ? What is are its units?
Voltage is a driving force that pushes the current around - volts, V
Resistance is caused by things such as components resisting the charge, ohms.
Relative sizes of the voltage and resistance decide the size of the current. If voltage is increased…
More current will flow. Less flows if resistance is increased !
How does power work?
Anything supplying electricity supplies energy. Power supplies transfer energy to the charge and this is transferred to components. Work is done as energy is transferred. Power is the rate at which electrical power supply transfers energy to an appliance.
What is power measured in?
Watts or kilowatts. 1 kW = 1000 W
A high power means…
Lots of energy transferred in a short time..
What is the formula for power?
Power (W) = voltage (V) * current (A)
