- #1
Ortix
- 64
- 0
Homework Statement
Homework Equations
There is not really a relevant attempt at a solution. I do however have the following question: According to the solutions and some reverse 'engineering' I found out that the voltage across R2 is the same as U1 = 60V. It's been years since I've done electrical engineering and I need to refresh my brain. It looks as if though U1 is across both R1 and R2.
The equation for the solution:
[itex]R_x = \frac{U_t - U_1}{\frac{U_1}{\frac{R_1 \cdot R_2}{R_1 + R2}} -I_1 - I2}[/itex]
I'm not quite sure what's going on here..
From what I understand is that the voltage which is 'left' from passing through R1 and R2 is used to calculate the resistance of Rx. So Rx = U/I where U = U_t - U_1. How is that possible? What about the other parallel connected resistors?
Furthermore, in the denominator of the equation I1 and I2 are subtracted from a calculated current. This is where the confusion of the first part of my question comes back. It's as if though the current which would come out of a compound resistor of R1 and R2 is equal to the Voltage across R1 divided by the compound resistance... WHAT?! Am I losing my mind?
EDIT:
I think this is what's going on:
Still not sure how the current is calculated from which I1 and I2 are subtracted:
[itex]\frac{U_1}{\frac{R_1 \cdot R_2}{R_1 + R2}} -I_1 - I2[/itex]
As in, I don't understand how that's valid.
Last edited: