Dòng điện\(i=2\cos \left(100\pi t-\frac{\pi }{3} \right)\left( A \right)\)

* Hướng dẫn giải

• \({{Z}_{L}}=100\,\Omega ,\,{{Z}_{C}}=200\,\Omega \to Z=100\sqrt{2}\,\Omega \to {{U}_{0C}}=400\,V;\,\,{{U}_{0}}=200\sqrt{2}\,V.\)
• \(\tan \varphi =\frac{{{Z}_{L}}-{{Z}_{C}}}{R}=-1\to {{\Phi }_{u}}-{{\Phi }_{i}}=-\frac{\pi }{4}\to {{\Phi }_{u}}-{{\Phi }_{{{u}_{C}}}}=\frac{\pi }{4}\)
• Khi \({{u}_{C}}=200\sqrt{2}=\frac{{{U}_{0C}}\sqrt{2}}{2}\oplus \leftrightarrow {{\Phi }_{{{u}_{C}}}}=-\frac{\pi }{4}\xrightarrow{\left( * \right)}{{\Phi }_{u}}=0\leftrightarrow u={{U}_{0}}=200\sqrt{2}\,V.\)