Diodes.

THEORY:

http://upload.wikimedia.org/wikipedia/commons/8/83/Diode_pinout_en_fr.svg

Diodes are a component in a electrical circuit that allows current to flow one way and not the other and is made of two semi-conductors which mean they are both semi insulators and conductors. When diode is connected in a circuit, the current flows through the diode and the rest of the circuit. This is known as  forward bias. This makes the electrons and holes in the diode push together towards the boundary layer which then makes the electrons easier to pull into the holes and allows current flow throughout the circuit. When diode is put in reverse in the circuit, this is called reverse bias meaning electrons
and holes move away from the boundary layer were it becomes harder to pull electrons into the holes. This would mean that voltage/current will stop at the diode and wont flow anymore throughout the circuit.


TEST:


When multimeter is connected to the diode in forward bias, the current/voltage will flow through the diode which will give a reading on the multimeter. When is reverse bias, the current/voltage flow will arrive at the diode and sit there resulting in current/voltage not flowing throughout circuit. When taking readings for current, the circuit needs to be broken for that reading. So when in forward bias the diode is being a conductor and in reverse bias it be becomes a insulator but when its a zener diode current/voltage can flow both ways . Zener diode allows current/voltage to flow in both direction, this is because zener diode are used mainly for high voltage circuit and bleeds off excess current/voltage so that components in the circuit are safe.

REFLECTION:


Diode are important for a number of reason but mainly because it is able to send current/voltage flow in one direction and not the other. If there were no diodes in a alternator, the A.C  that the alternator generates could not be rectified to D.C, this is possible due to the diode on the rectifier within the alternator.