회로이론
회로이론
역률
2003.8 기출
\(R=50\Omega\), \(L=200\)mH 직렬회로에 50Hz 전원을 걸 때 역률[%]은?
- ① 62.3 정답
- ② 72.3
- ③ 82.3
- ④ 92.3
📖 해설
역률 \(\cos\theta=\dfrac{R}{Z}\)
\(X_L=2\pi\times50\times0.2=62.8\Omega\), \(Z=\sqrt{50^2+62.8^2}=80.3\Omega\).
\(\cos\theta=\dfrac{50}{80.3}=0.623=62.3\%\).
\(X_L=2\pi\times50\times0.2=62.8\Omega\), \(Z=\sqrt{50^2+62.8^2}=80.3\Omega\).
\(\cos\theta=\dfrac{50}{80.3}=0.623=62.3\%\).