PHY 182 1st Edition Lecture 25Outline of Last Lecture I. Resistors in SeriesII. Resistors in ParallelOutline of Current Lecture I. When a Capacitor is ChargingII. When a Capacitor is DischargingCurrent LectureWhen a Capacitor is Charging- The initial current through a resistor can be found by dividing the voltage drop acrossthe resistor by the resistance value.- After the switch is closed, the current can then be calculated as the total emf of the battery divided by the resistance.- When a capacitor becomes fully charged, the current approaches zero and the voltage drop is equal to the emf of the battery.- The final charge does NOT depend on resistance.- Charge increases exponentially with respect to time when the capacitor is charging and current decreases exponentially.- The time constant (abbreviated by Greek letter tau) is equal to the product of resistance of capacitance. The value of the time constant tells you how quickly the capacitor charges.When a Capacitor is Discharging- When you connect a capacitor to a resistor instead of the batter, the capacitor beginsto discharge.These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- The functions of charge and current with respect to time are very similar to the previous case. In fact, the equation for current is exactly the same for a discharging capacitor as a charging capacitor.- Equivalent capacitance is calculated oppositely from equivalent resistance.- When capacitors are in series, the equivalent capacitance is calculated in the same way as resistors in parallel and vise
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