inductor current leads
An inductor is an energy storage device. It can be as simple as a single loop of wire or consist of many turns of wire wound around a special core. Energy is stored in the form of a magnetic field in or around the inductor. Whenever current flows through a wire, it creates a magnetic field around the wire. By placing multiple turns of wire around a loop, we concentrate the magnetic field into a smal|er space where it can be more useful. When you apply a voltage across an inductor, a current starts to flow. It does not instantly rise to some level, but rather increases gradually over time. The relationship of voltage to current vs. time gives rise to a property called inductance. The higher the inductance, the longer it takes for a given voltage to produce a given current. Whenever there is a moving or changing magnetic field in the presence of an inductor, that change attempts to generate a current in the inductor. An externally applied current produces an increasing magnetic field which in turn produces a current opposing that applied externally, hence the inability to create an instantaneous current change in an inductor. This property makes inductors useful as filters in power supplies.
A capacitor is a passive electronic component that stores energy in the form of an electrostatic field. In its simplest form, a capacitor consists of two conducting plates separated by an insulating material called the dielectric.
It is difficult to fabricate inductors onto integrated circuit (IC) chips. Fortunately, resistors can be substituted for inductors in most microcircuit applications. In some cases, inductance can be simulated by simple electronic circuits using transistors, resistors, and capacitors fabricated onto IC chips.