. Hawkins electrical guide. Questions, answers & illustrations; a progressive course of study for engineers, electricians, students and those desiring to acquire a working knowledge of electricity and its applications; a practical treatise. diagram by the solid curve, tolag behind the pressure wave, indicated bythe dotted curve. Following the curves starting from the left end of the horizontal be noted that the current starts after the pressure starts and reverses after the pressurereverses; that is, the current lags in phase behind the Pressure, although the frequency ofboth is th
. Hawkins electrical guide. Questions, answers & illustrations; a progressive course of study for engineers, electricians, students and those desiring to acquire a working knowledge of electricity and its applications; a practical treatise. diagram by the solid curve, tolag behind the pressure wave, indicated bythe dotted curve. Following the curves starting from the left end of the horizontal be noted that the current starts after the pressure starts and reverses after the pressurereverses; that is, the current lags in phase behind the Pressure, although the frequency ofboth is the same. Lag and Lead.—Alternating currents do not always keep instep with the alternating volts impressed upon the circuit. Ifthere be inductance in the circuit, the current will lag; if therebe capacity, the current will lead in phase. For example, ,288, illustrates the lag due to inductance and fig. 1,289, thelead due to capacity. IIAUKIXS ELECTRICITY Ques. What is lag? Ans. Lag denotes the condition where the phase of onealternating current quantity lags behind that of another. Theterm is generally used in connection with the effect of induct-ance in causing the current to lag behind the impressed pressure. 1 A l/\ a A A A. Fie. —Pressure and current curves illustrating lead. The effect of capacity in a circuitis to cause the current to rise to its maximum value sooner than it would otherwise do;capacity produces an efTd I e opposite of inductance. The phise rt between current and pressure with current leading is shown graphically by the two arma-ture positions in full and dotted lines, corresponding respectively to current and pressureat the beginning of the cycle. Ques. How does inductance cause the current to lagbehind the pressure? Ans. It tends to prevent changes in the strength of thecurrent. When two parts of a circuit are near each other, sothat one is in the magnetic field of the other, any change in thestrength of the current causes a corresponding c
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