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Signs of the voltage drops in this LC Circuit
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[QUOTE="Delta2, post: 6518667, member: 189563"] In DC circuits, once you chose a positive direction for the current then the polarity of the voltages for all elements, R,L,C is that is positive at the end of the component that the current enters into , and is negative at the end of the component where the current exits from. So in your example the top ends of the inductor and the capacitor are positive and the lower ends are negative. However it might turn out that after you done the current calculations that the current is negative, which means that it flows opposite to the positive direction you have initially chosen, so the current directions and polarities will have to be reversed . But that's something you will know after you have done the calculations. In AC circuits, for resistors the current is in phase with the voltage, which means that similar to DC circuits the polarity is known once you know the direction of current. However for inductors and capacitors the current has a phase difference of ##\pi/2## and ##-\pi/2## respectively with the voltage, which means that the current might be positive while the voltage negative. You need to know the exact moment in time, so you can determine the exact phase , and then to determine whether the current and voltage are positive or negative. PS. I was partially wrong in the first paragraph, even in DC circuits you might have a current flowing in a component from the negative end of the component to the positive end. This happens when a capacitor or an inductor are discharging, that is when they give their stored electric or magnetic field energy back to the rest of the circuit. Then the current [b]inside[/b] the inductor flows from its negative to its positive end, while in the rest of the loop where the inductor is attached to, flows from the positive to the negative end. [/QUOTE]
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Signs of the voltage drops in this LC Circuit
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