An electrical
current is a flow of electrical charge. Metals are good conductors
of electricity and in a metal the charge is carried by free
moving electrons which have a negative charge.
In order for an electrical current to flow there must be a complete
circuit. For key facts about electrical circuits click here.
Electrical
current can flow through liquids and in a liquid the charge
is carried by moving ions.
Electrical
Charge
Electrical
charge is measured in units called coulombs (C). An electrical
current is the rate at which charge flows.
A
current of 1 Amp is a flow of 1 coulomb of charge every second.
The
potential difference (p.d.), measured in volts is also related
to charge. The potential difference is the energy that is transferred
for every one coulomb of charge flowing:
If
the potential difference is 10V then 10 joules of energy are
transferred each time a charge of 1 coulomb passes through.
If the potential difference is 5V, 5 joules of energy are transferred
for each coulomb of charge.
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