see leading and lagging all of this is with respect to some base phasor . the concept of leading or lagging current is wrt voltage . draw a horizontal line (positive x ) say this is voltage phasor. Now if you have current with +theta angle (anticlockwise) then you have leading current . This is the case in capacitor . while if your current is at -theta (clockwise) than it is lagging . this is the inductor case . Now this base voltage phasor can also be at some angle not necessarily zero .
Now practical meaning is that we have all current voltages sinusoidal lagging current means first voltage's sine wave will attain its peak value and then current's wave will attain its peak value .vice versa for leading
When the current is out of phase with the voltage, energy is traveling forward and back to the source, over the AC cycle. If the inductor or capacitor had no loses, there would be a net zero power transfer. Capacitors and inductors charge and discharge at different phases of the AC cycle.
If a device /load is reactive, only the in-phase part transfers energy, so if you can balance inductance with a capacitor the reactive part of the current cancels and reduces the current to only the useful part, which reduces the power transmission losses.
Leading current is an alternating current that reaches its maximum value up to 90degrees ahead of the voltage that produces it.
Lagging current on the other hand is the alternating current that reaches the maximum value up-to 90 degrees behind the voltage that produces it.
just think. there is only capacitor is connected with voltage source now. as voltage source is a.c when voltage increasing in capacitor charge will go from one plate to another. so current in circuit will flow.
it means when voltage just connected maximum charge will flow. as increase with source voltage charge flow decrease.because voltage across capacitor is increasing and at peak value of source voltage. voltage across capacitor is also maximum means no charge will go one plate to another. means no current.
Practical meaning please
