help me solving this circuit for unknown values

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rudr_p

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The resistance X and Y has to be found out and the only given values are Vd,V and Resistance R.


I tried but somehow, I cannot figure it out.
and suppose if we have the voltage V when the value of resistance of known resistance R is infinite/open circuit that means the cicuit only contains X and Y. is it possible to find the resistance out, I mean by combining the upper two conditions

The only given values are the value of R,Vd and V.
Its an DC earth leakage detector circuit
Click to expand...



Thank you
 
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rudr_p said:
The resistance X and Y has to be found out and the only given values are Vd,V and Resistance R.
Click to expand...
There is no unique solution.
For example, if V = Vd/2, then the voltage across Y is the same as the voltage across R and X. So in that case resistance Y must be equal to the parallel combination of R and X.

rudr_p said:
...and suppose if we have the voltage V when the value of resistance of known resistance R is zero...
Click to expand...
If resistance R is zero then voltage V must be zero.
 

@godfreyl I don't understand your explaination.
If the resistance R is zero then the voltage cannot be zero but there will be some voltage between those point showing the drop in X.
 

You can find the ratio X/Y, but without mmore information there is no way to find actual values.

Let K = 1/(1/R + 1/X) so K is the resistance of X in parallel with R, then the circuit is simply a potential divider V/Vd= K / K+Y, I will leave the algebra to get the actual ratio as an excersise.

And if R is zero then V is zero and all the voltage is dropped across Y, you cannot develop a voltage across zero ohms and R is in parrallel with X.

Regards, Dan.
 

Omg!!! sorry!!! godfreyl and Dan Mills , I actually wanted to say that resistance R is open as in suppose there is no R in the circuit when measuring the voltage V....
 

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