KNOW ABOUT BASIC ELECTRICAL AND ELECTRONIC DEVICES

Nowadays, we are familiar with the, electricity and various electrical instruments. There are many things  e.g light, fan, TV, refrigerator,switch,fuse etc. in our house. We use this instruments. But we frequently listen some terms and devices name viz. voltage, current, AC Current, DC Current, resistor, transformer, capacitor, LED, inductor etc. which we don't use these directly. But, amazing fact is that, the instruments which we daily use, are made of these(resistor, capacitor etc.). 
Let's discuss these. Here, I don't discuss these so deeply.

• What is Voltage? and  What is Current?

Voltage( Potential difference) represents the force. And Current represents the flow of electrons in the circuit. We (who are the basic users or novice) need not know much about this.

It is a image of mobile charger.See what is written as input and output

The unit of
voltage is volt (v)
and
current is ampere(A).
1mA=(1/1000) A










You obviously heard the term watt. This is the unit of power. It refers the amount of energy consumed per second.

It is the image of LED bulb.See its power.

Generally watt is written as W.
If you have two bulb of 25W and 100W. The bulb of 25W consumes less electrical energy.It does not always mean that bulb of lower power deliver lower light energy(i.e brightness). LED bulb consume less energy but deliver more light energy.

• What is DC Current? and What is AC Current?

 Electron always flows from negative terminal to positive terminal.

But conventionally ,direction of current is assumed just opposite i.e positive to negative terminal. In adjacent diagram, the blue particle is electron.

DC Current:
 DC Current (Direct Current) flows in a constant direction.

Here arrow sign show the direction of current.

The direction cannot be changed unless arrangement is changed.
From battery we get dc current.

Symbol of DC Current.

• AC Current:

AC Current (Alternating Current)

Here arrow sign show the direction of current.

is an electric current which periodically reverse direction. You should keep the fact in mind that current flows from positive to negative. So, here the positive and negative terminal (of source) are periodically changed.
Our household electric supply is a example of AC source.

Symbol of AC source.

• What is Resistor?

Resistor is an electronics device which oppose the

Resistors

current (flow of electron). In fact voltage and current depends on each others. The power ( I have used the term 'power' as a normal sense, not power=work/time or power=energy/time) of resistor is called resistance.
The relation between voltage,current,and resistance is V=IR .[V= Voltage,I=current,R=resistance]. It is known the mathematical expression of Ohm's law.

Symbol of Resistor.

The unit of resistance is Ohm ( Ω ).
We use regulator for controlling the speed of fan. In fact, it is a type of variable resistance box. There are some resistors ( suppose 50Ω, 100Ω, 200Ω, 300Ω )in the regulator. When we turn the knob of the regulator, we actually select a resistor (or resistance) as well as current which flowing through the fan.
    We can measure the value of resistor seeing the color printed on it.

How to measure the value of a carbon resistor without any device.

• What is Transformer? 

Transformer is an electrical device which can increase or decrease voltage.

Transformer

 Suppose, we have 220 V AC source ( i.e our household electrical supply line ). Now, we need 100 V supply. To get 100 V AC source from 220 V AC source, we use a transformer( a step- down transformer).

In other hand, to get a higher value of voltage from a lower voltage (i.e to get 300 V from 220 V ), we use a step -up transformer.

Always keep in mind that transformer can only be used for AC source. So, we can increase or decrease the AC voltage using transformer directly.

Symbol of Transformer

• What is Capacitor ?

Capacitor is a device which can store charge. Capacitor is used for various purpose. Suppose, in a circuit, AC current and DC current are mixed up. Now,

Capacitor

we want to block DC but not AC. TO do so, we can use a proper capacitor (blocking capacitor).

various types of capacitor

The unit of capacitor is F ( Farad). 

µF is read as micro Farad.

Symbol of Capacitor

    Capacitor store charge. Hence after switching off the source of a circuit, it ( capacitor ) may give a electrical shock. 

• What is Inductor ?

Suppose, in a circuit, AC current and DC current are mixed up. We want to block AC but not DC. SO, in this situation, we may use a inductor to do so.

Inductor

Symbol of Inductor

Do you recall, what we use to block DC without disturbing AC current ?

      When we convert a AC current into DC,  the output don't become entirely DC ( pure DC ). There is a small component of AC. Using inductor we block AC current. Actually, it act as filter.

• What is Diode?

Diode is an electronic device.

The upper part is the symbol of a diode.

It allow the current to pass only one direction. Using this characteristics, we can convert AC current into DC.

    If the diode is made using semiconductor (Silicon, Germanium), there is two part, one is 'p-type' and another is 'n-type'. And hence, sometimes diode are called p-n junction diode.

• What is LED?

It is a special type of p-n junction diode.

Left:LED; Right:Schematic view of LED

Full form of LED is Light Emitting Diode. When  a suitable current is applied to it (LED), electrons are recombined with holes. Hence light emit from the junction( the joining line of 'p-type' and 'n-type').

LED

Symbol of LED

  

I have not discussed in deep because I have written this for beginners or novices.

If you want to know much more  or you have a question or doubt , PLEASE comment. 

 

Functions of Bass, Treble and Volume options in an Amplifire. 

 

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