, ánh sáng nhấp nháy là một vấn đề nghiêm trọng. Phát điện và hệ thống phân phối không đủ cứng để hấp thụ các dòng biến động lớn. Cơ sở sản xuất sử dụng một số lượng lớn các máy bơm và máy nén của thiết kế qua lại. Do yêu cầu công suất dao động của họ, ánh sáng nhấp nháy là một vấn đề thường xuyên. | FIGURE Variation of VC with time and with time constant RC. The significance of the time constant is again as indicated under the discussion for capacitors. In this example the voltage across the inductor after one time constant will equal V in two time constants V and so on. The significance of the time constant T in both capacitive and inductive circuits is worth emphasizing. The time constant reflects how quickly a circuit can recover when subjected to transient application of voltage or current. Consider Eq. which indicates how voltage across a capacitor would build up when subjected to a sudden application of voltage V. The larger the time constant RC the slower the rate of voltage increase across the capacitor. If we plot voltage vs. time characteristics for various values of time constant T the family of graphs will appear as shown in Figure . In inductive circuits the time constant indicates how quickly current can build up through an inductor when a switch is closed and also how slowly current will decay when the inductive circuit is opened. The time constant is an important parameter in the transient analysis of power line disturbances. The L-C combination whether it is a series or parallel configuration is an oscillatory circuit which in the absence of resistance as a damping agent will oscillate indefinitely. Because all electrical circuits have resistance associated with them the oscillations eventually die out. The frequency of the oscillations is called the natural frequency fO. For the L-C circuit fO 1 2 Lc 2002 by CRC Press LLC Vc V y y FIGURE Oscillation of capacitor voltage when L-C circuit is closed on a circuit of DC voltage V In the L-C circuit the voltage across the capacitor might appear as shown in Figure . The oscillations are described by the Eq. which gives the voltage across the capacitance as VC V V VCO cos O where V is the applied voltage VCO is the initial voltage across the capacitor and
