How Do You Calculate Transformer Efficiency with Given Power and Voltage?

Thread starter Nightwatchman
Start date May 3, 2009
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Efficiency Transformer

AI Thread Summary

To calculate the efficiency of a transformer with 13W of primary power, the relevant equation is efficiency = (Psec / Pri) * 100. The primary voltage is given as 120V, while the secondary voltage is 12V and the number of turns in the secondary (Np) is 90. There is confusion regarding the number of primary turns (Np), as it is initially stated as unknown but later assigned a value of 90. Clarification is needed on whether Np is indeed 90 or if it remains unknown for the calculation. Accurate values for both primary and secondary turns are essential for determining the transformer's efficiency.

May 3, 2009

Nightwatchman

Homework Statement

What is the the efficiency of a transformer with 13w of primary power.
120Vp, Np unknow
12Vs, 90Np

Homework Equations

The Attempt at a Solution

eff= Psec/ Pri * 100

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May 4, 2009

rl.bhat

Homework Helper

120Vp, Np unknow
12Vs, 90Np
In first line you say Np is unknown and second line you say Np = 90. which is correct?

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