How can i put the polaritiy of E thevenin's ?

[bibo_dvd]

Hello guys ..

i need your help with something

in this photo i understand the way to calculate R thevenin's and the way to calculate E thevenin's

but i couldn't understand

why did we put the polarity in this way ??

i mean why can't we put switch the polarity of the battery ??

thanks guys

 

[gneill]

why did we put the polarity in this way ??

Because solving the potential dividers shows that Vb is greater (more positive) than Va.

i mean why can't we put switch the polarity of the battery ??

If you want to turn the battery symbol around you can do so by specifying the battery voltage to be -6V rather than +6V. Technically this is allowed, but it may bother some who insist that a battery's positive terminal really should be positive with respect to its negative terminal

 

[bibo_dvd]

okay that's mean that we can turn the symbol of the battery if we turned "a" and "b" in the other side ??
i mean if we put b in the upper right side and a in the lower right side ?? :)

 

[gneill]

okay that's mean that we can turn the symbol of the battery if we turned "a" and "b" in the other side ??
i mean if we put b in the upper right side and a in the lower right side ?? :)

Sure, if you also move the ground symbol to the top so it stays connected to b.