diodes?

[Shark 774]

What is the point of a diode? If it is supposed to have no effect on the flow of charge in one direction and totally stop it in the other then why have it? When it's not doing anything then it's pointless and when it's totally stopping it why even have the circuit at all?? Unless you can have 2 currents flowing in opposite directions at the same time?? I'm a bit confused.....

[schnappy]

They're used in bridge recitifiers, LED's function as light sources. Being non-ohmic they can also be used as voltage regulators (usually zener diodes are used).

Open your text to the further electronics (detailed study) section and it'll make sense.

[xZero]

a diode requires a threshold voltage for the resistance to become 0, so like when the battery only supply 0.1v, the diode with a 0.7v threshold will block off the current. If the battery supplies a 0.8v, then the diode will use up 0.7v and opens up the current. So in a way a diode controls how much the current can go through.

[Shark 774]

Right, thanks guys. I totally forgot about the further electronics section!