[Zishi]

Here's a question from a past paper:

State two advantages of the use of alternating voltages for the transmission and use of electrical energy.

I understand that one use is to reduce the power loss in cables by transmitting power at very high voltages, but I don't know any other good advantage. Also I don't understand the second use given by the mark scheme, "can change voltage easily / efficiently".

Any help would be appreciated.

[Ari Ben Canaan]

(Original post by Zishi)
Here's a question from a past paper:


I understand that one use is to reduce the power loss in cables by transmitting power at very high voltages, but I don't know any other good advantage. Also I don't understand the second use given by the mark scheme, "can change voltage easily / efficiently".

Any help would be appreciated.

Imagine we transmitted electricity at a high voltage DC. Now imagine you need to step it down to charge up your iPod.

How easy it that going to be ?

Now imagine you are transmitting at AC.... Just prop a transformer in between you and the power station and voila ! You're iPod can now charge up.

[musabjilani]

^ What he said, you can use a transformer to easily step up or down the voltage. Also, you can convert AC to DC very easily using a rectifier, and so you can use an AC supply to run AC as well as DC devices, whereas it would be much harder to convert DC to AC, so you would only be able to run DC devices off a DC power supply.

[Zishi]

Alright, thanks to both of you.