Frequency of Generator + V of Capacitor

[kmj9k]

1. A 8.6 Hz generator is connected to a capacitor. If the current in the generator has its maximum value at t=0 s, what is the earliest possible time that the voltage magnitude across the capacitor is at a maximum?



2. I'm actually not sure which equations are relevant for this problem!



3. I'm afraid I don't understand the concepts behind this problem. I read in my book about oscillations in an LC circuit with no generator, but then I don't understand how this can be applied when there *is* a generator with its own frequency. Any help would be appreciated!

 

[Mentz114]

It depends on the waveform of the generator. If we assume sinusoidal then the voltage from the generator is V*cos(2*pi*8.6*t) which has its maximum V when t=0 as required. Find the formula that tells you how a capacitor charges and you're halfway there.

 

[berkeman]

It depends on the waveform of the generator. If we assume sinusoidal then the voltage from the generator is V*cos(2*pi*8.6*t) which has its maximum V when t=0 as required.

Except the problem statement says that the current is max at t=0, not the voltage. kmj9k, what is the relationship between voltage and current in a capacitor? Assume a sinusoidal waveform along the lines of what Mentz suggested...will the current lead or lag the voltage in a capacitor?