Compute DC electrical power from voltage and current, with the derived resistance and the energy used over a given time.
输入电压 U 与电流 I,求电功率。
| Item | Formula / Rule | Source / Standard |
|---|---|---|
| Single-phase power | P = U × I × cosφ, where cosφ is the power factor. | IEC 60050-131:2013, International Electrotechnical Vocabulary |
| Three-phase power | For a balanced three-phase circuit, P = √3 × line voltage × line current × cosφ. | IEC 60050-131:2013 & IEEE Std 1459-2010 |
| Power relationship | S² = P² + Q² relates apparent, active and reactive power in the power triangle. | IEEE Std 1459-2010, definitions for the measurement of electric power quantities |
家庭与车间配电回路功率核算、空开与线缆容量选型、设备同时率与负载评估。
电功率 P = U×I(电压×电流),直流与阻性交流适用;单位瓦特(W)。
由电压电流估算用电功率与配线/插座负荷;P 越大功耗越高。
含电抗的交流电路需用视在/有功功率(P=UI·cosφ);结果仅作估算,电气改造请遵规范并由专业人员施工。