Problem Set 1

Problem

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Find the core inductance and resitence of a transformer using measurmnets Voc=5V, Ioc=3A, and Poc =10W.

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Solution

Power is found only through resister

$Poc=Voc^{2}/R$

Both Poc and Voc are giving so solve for R

$R=Voc^{2}/Poc=5V/10W=2.5Ohms$

To calclate the core inductance we will use the formular for appearent power.

$S^{2}=P^{2}+Q^{2}$

$S^{2}=|Voc*Ioc^{*}|^{2}$

Subtituting in values aand solving gives $S^{2}=(5V*3A)^{2}=225(VA)^{2}$

$Q={\sqrt {P^{2}-Q^{2}}}$

${Z_{th}}={\frac {{\frac {N_{1}}{N_{2}}}{e_{2}}}{{\frac {N_{2}}{N_{1}}}{i_{2}}}}$