Basic Elements

Moving further towards our goal, we must first be able to recognize various elements required for making a complete electrical circuit.

Most of us studied or hear about basic elements being resistor, inductor, and capacitors but we never actually get to identify them.

Here we will look upon some very important components which are used mostly in any circuits.

Resistors: -

Resistors are nothing but a load and thus they consume power the same as any other equipment (TV, 
Fridge, Bulb etc…)

Let’s look at some of them available in markets.

 Resistors are available with different power ratings as shown in the picture. Starting from 0.25 Watts to over 10 Watts, power rating decides the maximum power it can dissipate.

Apart from the power rating, its resistance value is the next factor to decide upon. Starting from 0.5ohms, resistors of over 10 Megha ohms are available in the market.

These days, as the size of electronic circuits is getting reduced, another kind of resistors which are very very small in size are used in them. They are called SMD resistors.

You might find them in mobile phones, mini inverters, computers, etc… as shown:

So, next time if you want it, just go on the electronic component store and ask for a resistor with wattage rating and resistance value.

Well, they are very cheap (not more than 1 rupee), especially the ones to be used in general electronic circuits (0.25 watts).

Inductors and Capacitors

These are important electrical elements in AC circuits after resistors. Both Inductors and Capacitors are capable of storing energy for some period of time and discharging it back to the circuit, thus making average power zero. And this is the reason why inductors and capacitors are passive components, the same as resistors.

                                                                                                                                  Capacitor Types

But how does it help us?

The very popular example to understand this is a Battery.

A battery is nothing but a capacitor which can store energy for a quite larger period allowing us to use this energy in emergency and in any place.

So where do they store energy?

Capacitors store energy in the form of an electrical field while inductors in a magnetic field. (Link to Magnetic and Electric field)

Talking of their use in the circuits, they are mainly used in AC (Alternating Current) circuits.

In DC circuits, capacitors will block the voltage i.e. it will block the voltage and won’t allow current to pass through it, while an inductor in a dc circuit will work as a short-circuited connection and thus will be the same as a wire connected across it.

At some point when an alternating signal consists of some percentage of dc component, capacitor helps to filter out the dc component and pass out the alternating signal only.

                    

Inductors Types

While inductor being the only source of magnetic field generation, it is thus used everywhere from a ceiling fan to the turbo generators used in power plants. This is because all the rotating machines make use of the concept of a magnetic field. (Link to Electromagnetic laws of induction)

While capacitor opposes the change in voltage across it, inductor opposes the change in current through it.

Point to note:-

Sudden change in voltage across the capacitor in a very short period will cause a very high current through it and thus is harmful. Similarly, a sudden change in the current flowing through an inductor will induce a very high voltage across the inductor and is harmful.