# Symmetry in circuits involving Resistors

#### logearav

Joined Aug 19, 2011
243
Hello friends,
Find attached a problem involving symmetry in circuits involving resistors. Its been mentioned that by symmetry the current in part ab and ad will be equal.
The current i branches to part d, o and b at the same time. Then how could symmetry is applicable only in ad and ab not ao?

#### logearav

Joined Aug 19, 2011
243
Hello friends,
Find attached a problem involving symmetry in circuits involving resistors. Its been mentioned that by symmetry the current in part ab and ad will be equal.
The current i branches to part d, o and b at the same time. Then how could symmetry is applicable only in ad and ab not ao?
View attachment 94870
Also please refer the following attachment too.
Why there is symmetry as mentioned?

#### WBahn

Joined Mar 31, 2012
26,398
Then how could symmetry is applicable only in ad and ab not ao?
Are the resistors all the same value? That's critically important to know.

Assuming so, who says that it doesn't apply to ao?

#### WBahn

Joined Mar 31, 2012
26,398
Also please refer the following attachment too.
Why there is symmetry as mentioned?
Well, look at those two branches. Is there any reason for the current in one to be different than the current in the other?

#### logearav

Joined Aug 19, 2011
243
Well, look at those two branches. Is there any reason for the current in one to be different than the current in the other?
Thanks Mr.WBahn. By symmetry does it mean that the magnitude of current is same in every branch?
Yes, the resistances are of equal value.

#### WBahn

Joined Mar 31, 2012
26,398
Symmetry does not necessarily mean that the magnitude of the current is the same in every branch, just in those to which the particular symmetry argument applies.

#### logearav

Joined Aug 19, 2011
243
Symmetry does not necessarily mean that the magnitude of the current is the same in every branch, just in those to which the particular symmetry argument applies.
Thanks. So what exactly symmetry means with respect to current, sir?

#### WBahn

Joined Mar 31, 2012
26,398
It means that there is no reason for the current in one resistor to be different than the other. The usual test for this is that you could swap the paths and nothing would change.