Saturday 30 March 2013

2.7 understand the difference between mains electricity being alternating current (a.c.) and direct current (d.c.) being supplied by a cell or battery

Direct current flows in one direction only. It is supplied by cells and batteries. It comes out as a straight line on an oscilloscope.

Alternating current changes from one direction to another rapidly. Mains electricity is alternating (interestingly this is because the electricity has to go through transformers on the national grid which only work on ac current, although that's not relevant here!)

8 comments:

  1. I just wanted to say thank you for all your help x you have made me get an A when all my teachers predicted me a C x I hope you keep helping people and make people achieve the best they can achieve x
    Thank you again
    Frankie

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    Replies
    1. Did you use this to revise on it own with past papers or did you use a text book also

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    2. I just used some of Hannah Help and I got an A*A in my Mocks

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  2. Very helpful website:
    http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa_pre_2011/electricity/mainselectrev5.shtml

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  3. thank you so much for all this hope i get an A

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