Remembering the phase difference

The mnemonic "ELI the ICE man" can be helpful in keeping track of the phase between the voltage and current in an AC circuit.

In a circuit with only an inductor and an AC power source, there is a 90^o phase difference between the current and voltage - the voltage leads the current by 90^o. This is the ELI part...with an inductor (L), the emf (E) is ahead of the current (I).

In a circuit with only a capacitor and an AC power source, there is also a 90^o phase difference between the current and voltage - the voltage lags the current in this case. This is the ICE part...with an capacitor (C), the voltage emf (E) is behind the current (I).