Slides in this set
When electric charges move in a wire, we say that an electric current flows in the wire. It's
like the way a current of water flows in a river.
For an electric current to flow, we need two things:
something to make the electricity flow, such as a battery or power pack
a complete path for the current to flow in. This is called an electric circuit.…read more
· Voltage is a measure of the difference in electrical energy between two parts
of a circuit. The bigger the difference in energy, the bigger the voltage.
· Voltage is measured in volts.
· Voltage is measured using a voltmeter. Some types of voltmeter have a
pointer on a dial, but most have a digital readout. To measure the voltage
across a component in a circuit, you must connect the voltmeter in parallel
with it.…read more
· Resistance is measured in ohms. It can be calculated from the potential
difference across a component and the current flowing through it. The total
resistance of a series circuit is the sum of the resistances of the components
in the circuit.
· An electric current flows when electrons move through a conductor. The
moving electrons can collide with the atoms of the conductor. This makes it
more difficult for the current to flow, and causes resistance.…read more
· In parallel circuits different components are connected on different branches of the wire. If
you follow the circuit diagram from one side of the cell to the other, you can only pass
through all the different components if you follow all the branches.
· In a parallel circuit, if a lamp breaks or a component is disconnected from one parallel wire,
the components on different branches keep working. And, unlike a series circuit, the lamps
stay bright if you add more lamps in parallel.
· Parallel circuits are useful if you want everything to work, even if one component has failed.
This is why our homes are wired up with parallel circuits.…read more