Potential Divider Equation (Rearranging)

[rindishy]

Hi.

I'm currently learning about potential dividers and need some help with rearranging the formula.

I've managed to rearrange it to make V_in and R₁ the subject, but I'm having trouble rearranging for R₂.

Can someone help? My maths isn't great, so an explanation would be great. Thanks.

The formula is:

V_out = V_in x R₂/(R₁ + R₂)

 

[Bystander]

What were you wanting from the rearrangement? You've omitted V_out. You can't be trying to eliminate it as a variable.

 

[rindishy]

I want to be able to work out R₂. So if for example I had a question where I was given V_out, V_in and R₁, but not the value of resistance of R₂.

i.e.

R₂ =

 

[Bystander]

Okay. Remember you HAVE to treat both sides of an equation the same way, whatever you do to one side, you do to the other; and you want R₂ in terms of the other three variables. What's a good place to start? How about multiplying both sides by (R₁+R₂) and collecting terms containing R₂ on one side of the equation? Take a stab at it and I'll be right here online for a while --- football games aren't on yet.