Solving a Problem with Transformer Load Resistance and Source Resistance

[RigelulZ]

Weird Transformer Problem :(

Homework Statement

"In the transformer shown in the figure below, the load resistance RL is 44.0 Ω. The turns ratio N1/N2 is 2.10, and the rms source voltage is ΔVS = 77.0 V. If a voltmeter across the load resistance measures an rms voltage of 26.5 V, what is the source resistance Rs?"

Homework Equations

See attachment for Equation of R_s

The Attempt at a Solution

I plugged in my values for the formula i got for R_s but got it wrong? I got 77.4 Ohms

Does anybody know what I'm doing wrong? Because i sure don't.

Any help will be greatly appreciated, thanks in advance!

-Rígel

 

[Andrew Mason]

The Attempt at a Solution

I plugged in my values for the formula i got for R_s but got it wrong? I got 77.4 Ohms

Does anybody know what I'm doing wrong? Because i sure don't.

How are you analysing the problem?

Can you determine the voltage drop across the source resistance? Can you determine the power in the secondary coil? How is that related to the power passing through the primary coil?

AM

 

[RigelulZ]

How are you analysing the problem?

Can you determine the voltage drop across the source resistance? Can you determine the power in the secondary coil? How is that related to the power passing through the primary coil?

AM

Wow, you were absolutely right, i did it through power like you instructed and it worked like a charm.. I also learned not to round too soon into the problem.. :/

Thank you!