Solving a Problem with Transformer Load Resistance and Source Resistance

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SUMMARY

The forum discussion addresses a transformer problem involving load resistance (RL) of 44.0 Ω, a turns ratio (N1/N2) of 2.10, and a source voltage (ΔVS) of 77.0 V. The user initially calculated the source resistance (Rs) as 77.4 Ohms but received incorrect results. Through community guidance, the user learned to analyze power relationships in the transformer, leading to a successful resolution of the problem by avoiding premature rounding in calculations.

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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?"


circuit.gif




Homework Equations



See attachment for Equation of Rs

Rs.gif



The Attempt at a Solution



I plugged in my values for the formula i got for Rs 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
 
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RigelulZ said:

The Attempt at a Solution



I plugged in my values for the formula i got for Rs 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
 


Andrew Mason said:
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!
 

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