Introducing Elements

Let us begin the journey with the introduction of the most basic part, obviously which is WORTH.
Since childhood, we have been taught that the most basic elements of electrical circuits are  Resistor, Capacitors, and Inductors, But as we move on, we discover that there are many other elements to complete the electrical circuits. With a varying property exhibited onto the circuits, they are characterized in some very technical manner. 

ACTIVE AND PASSIVE COMPONENTS

Somewhere between the lines we read of the resistor being a PASSIVE Element, but what about others and what does this Passive really mean?
Before defining what REALLY active and passive elements are, let it be clear that Inductors and Capacitors are too Passive components.

Active Elements:

Or we say in general words that, an Active Component are devices/elements which require an external source to their operation. Or
Talking Technically: "Element that is capable of furnishing an average power that is greater than zero over an infinite time interval."

Passive Elements:

Basically just the opposite. Passive components are those devices/components which doesn't require an external source to their operation.
But the above statement doesn't really seem to be all true. Is it?
Rather actually they are defined to be the "Elements that cannot supply an average power that is greater than zero over an infinite time interval."

1. 

Let's be Practical Now:
A diode is an active component, why? Doesn't it seems to have its own source, but still?
okay!
If we connect a diode in a circuit, the current wouldn't flow through it, that's because it has got to have some specific voltage conditions which need to be followed that the supply voltage should be or ed some specific voltage(0.7 or 0.3). Similarly for BJT, FET, MOSFET, SCR, etc.

While there's no such in case of resistors. Through a resistor, the current will flow even with 0 or infinite input voltage (proportionally though).

Further, we will learn how to make use of these elements and try to relate those with the circuits around us   .. :)