Electronic components are simply elements that can be put into a circuit. There are countess electronic components, which range from the absolutely essential (wires, power sources) to the entertaining but totally optional (bells, flash bulbs).
Each of these is assigned a symbol that can be used to indicate it within a circuit diagram, and each one is used every day by professional electricians and engineers working all over the world. With an understand of these topics, you will be able to understand what people are talking about when they talk about circuits, no matter where you are or who you talk to.
Active components are the parts of a circuit that absolutely need a power source to function. These components can increase the electricity in a circuit, though they do not always do so. It is possible that they have a power source in addition to the alternating current flowing through the circuit, though it is not critical that they have one.
Ultimately, the key aspect of active components is that they can produce a net increase in the electricity in a circuit, though they do not have to.
Another common passive circuit component is the high voltage ceramic disc capacitor. Capacitors store energy inside themselves when a current is passed through the circuit. Capacitors have two sides, one that is positive and one that is negative, and the two sides are separated by an insulator. This creates a voltage difference, and the resulting electrostatic field holds energy that can be harnessed by the circuit.
Because capacitors are able to store energy, they are useful for moderating circuits that experience variable currents. Capacitors can store or release their energy, as necessary, to increase or decrease the current flowing through the circuit.