Question

Difference between controlled ac voltage and variable dc

Answer 1

Answer:

1.The DC voltage you have now is NOT fixed in its value(because supply AC voltage is always variable due to load fluctuation).

2.Now,if you draw power from this DC source at different loads(or different current requirement),the voltage you will get will be different in each case.(voltage varies due to source loading).

This was Variable DC voltage you got.

Now,let’s analyse the case of fixed DC voltage.

Got AC supply(practically variable)? rectify it.now you have Variable DC supply.

ADD a DC filter(C,LC) to eliminate ripples(known as DC fluctuations) and at final stage , a DC regulator.

In this case,even though supply AC voltage varies,it is not going to effect my final DC output(also,ripples will be eliminated).

Connect loads of variable value(within rated limits),drawing different values of current from the DC supply,the voltage output will not vary with current fluctuation or source loading will not come into effect.(due to addition of regulator)

Explanation: