What is the necessity of ground in every circuit ?

on Thursday, 19 September 2013
Do you ever thought why we have ground connection in every circuit(in general) ? what is  the necessity of ground connection ? what actually ground is? why ground is always consider as zero voltage? What happen if we don't give ground?
To know answers of all these questions, read this post.I'm explaining with simple and comprehensive way of understanding.
First let us have a look what  actually definition of  'Ground' is..
Ground(wikipedia): Ground or earth can refer to the reference point in an electrical circuit from which other voltages are measured, or a common return path for electrical current, or a direct physical connection to the Earth.
I know your mind stuck at the above definition, dont worry i'll clear these points soon.
Before going into the actually concept, lets have a general question
"how you measure any quantity in general? "
basically answer we get "by using measurement material" right.
Assume you need to measure 'cloth' and you have measuring material 'scale' made of a particular material say 'copper', assume a person in India and a person in Germany have the same type of scale with them.Person from India, he measures the cloth of 1meter and gives to his customer who is from Germany, but when he checks the cloth in  Germany then he found cloth is more than 1meter. Why it is so?
Because due to the hot sun in India copper scale expanded, but the scale in Germany remains the same because of the local temperature. so difference between both the quantities. In order to solve this problem, the material should be such it should not expand or contrast with general temperatures.
Remember the above example at the back of your mind, now answer the below question.
How can you make the ''line''  bigger without touching it(see below pic.), when i was in school  teacher asked the similar riddle.

answer is ,just draw a small line beside it to look the actual line big

Important point we realize from this riddle is that,  '' there is nothing like small or big, quantity will be decided  by comparing to any reference material."
The main point you should understand  by the above two examples are "we need some reference to measure any quantity" .
Now lets go back the top of the page and read the definition of ground once again..tik tik tik..
I think now you understood better that Ground is considered as reference point to measure voltages.If you want to know what is meant by voltage then refer this link
Why always ground is taken as zero voltage?
Answer is simple, your wish you take any value.. yes really, take as your wish. But if you take as zero then it will be easy for you to measure voltage of particular source. For example you measured voltage source and it shows 10v taking reference as ''zero'', then the same quantity will show ''15v'' if you take reference ground as 5. So, for the simplicity globally we consider as 'o'
What is the necessary of ground in every circuit?
Answer is ''to flow current all over the circuit" . To understand this, just see  below example.
We know current flows from higher potential to lower potential , similar to water which flows from higher to lower path. Consider a rectangular bowl(as shown below fig) and pore little water in it and place that bowl plate  without tilt, we can observe that water cannot flow all over the base of the bowl due to its even position.

Now just bend the position at one side and observe water flows in that particular direction.
Similarly, bowl is nothing but the circuit, and if current to flow in all the paths in the circuit, then all paths should be grounded(it means we are making electrons to flow in that low direction) , so by making all paths to ground then we are making electrons to flow in that particular direction. For homes and buildings ground is made to prevent electric shocks(google for more info).
Go back to the top of the page and now read the definition once again and come back...
I hope i made you to know why we always use ground for all the circuits and why it is always zero and so on :-)
Important Note: Above explanation is done by keeping in mind of  beginners (i.e beginners are my reference point) . Dont take it as a standard notes for your academics.



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