How is the rms current in the capacitor related to its capacitance and to the frequency? The answer, which requires
Capacitors in AC Circuits In analogy with resistance, we write:
Capacitors in AC Circuits
RC Circuits This phasor diagram illustrates the phase relationships. The voltages across the capacitor and across the resistor are at 90 ° in the diagram; if they are added as vectors, we find the maximum.
RC Circuits This has the exact same form as V = IR if we define the impedance, Z :