# What is an electric circuit?

An electrical circuit is a path where electrons flow from a voltage or current source. So the word electricity is derived from the word electron. A battery does not work by itself, if you hold it in the air there will be no passage of electric current. In general, an electronic circuit is a major medium for electrons to flow. Electric Circuit uses two forms of electrical energy. Electrical circuits include a device that powers charged particles of the current formation such as batteries or generators; Lamps, and electric motors. Basically, there are two types of current are flowing through the circuit.

• Alternating Current (A.C.)
• Direct Current (D.C.)

## What is the Difference between A.C. and D.C. Current?

We know that flow of electrons is called current. A.C. is the Alternating Current, which changes its path 50 times in a second. Whereas D.C. is the Direct Current which is not change its path or direction it follows the same direction at all. Because of Thomas Edison – DC power is generated by creating a magnetic field near the wire, causing the electrons to flow in a single direction, from negative to positive.

### A.C. Current

• The frequency of an Alternating Current is usually 50Hz or 60Hz.
• A.C. current can be used for many applications like fans, air conditioners, etc.

### D.C. Current

• Because Direct Current always follows in the same direction
• Most of the people are using D.C. power where the dynamics of electrical energy are required. Such as cell phones, vehicle batteries, etc., or where A.C. power is not available.

## What is a diode?

The diode is a semiconductor device that allows current to flow through one of the two terminals. It has low resistance to current on one side and very high resistance on the other. It is a vacuum tube consisting of two electrodes a plate

• Anode
• Cathode

Most of the diodes in an electric circuit are made of silicon, sometimes selenium or germanium is also used in the circuit. Since one diode allows electronic current to pass in one way but not the other, it is used as a rectifier to convert AC to DC current.

## Applications of Diode

Diodes are used in different places, so it is impossible to think of the whole electric circuit in a diode. Diodes can be used as signal limiters, switches, signal modulators, computers, mobile phones, voltage regulators, signal mixers, etc.

## Definition of Transistor

It is a semiconductor rectifier device that is used to amplify and convert electronic signals and power. When voltage or current is applied to one pair of terminals it changes to another pair. The output power can be higher than the input, a transistor can amplify the signal. The three leads of the transistor are below:

• Base
• Collector
• Emitter

## What is MOSFET?

MOSFET means a Metal Oxide Semiconductor Field Effect Transistor. It is a type of transistor used to amplify or convert electronic signals. Although MOSFET consists of 4 terminals, such as –

• Source
• Gate
• Drain
• Body

But body terminals and source terminals are often internally connected to each other, so only three terminals are present in electrical images. MOSFET acts as a common transistor in both digital and analog circuits. MOSFET is one of the most widely used transistors.

## Ohm’s formula

Ohm’s law is that the current flowing through an electronic circuit is proportional to the voltage difference between the two ends of that circuit V proportional to I

V = I R

## Current and Voltage

The flow of electrons through a current-carrying conductor is called current. The unit Amp of current is expressed by I. The pressure required to displace electrons is called voltage. The voltage is denoted by V, and the unit of voltage is Volt.

## Details in Transistor

It is a semiconductor rectifier device that is used to amplify and convert electronic signals and power. A transistor has 3 terminals. When voltage or current is applied to one pair of terminals it changes to another pair. The output power can be higher than the input, a transistor can amplify the signal. Most transistors are found in integrated circuits. The three leads of the transistor are below:

• Base,
• Collector
• Emitter.

The transistor is made up of two p-n junctions inside an electronic device made of a semiconductor. Maybe NPN junction or PNP junction has three terminals that can amplify an electronic signal and switching any signal or electric power.

Transistors can be classified in different ways from different perspectives. Modern research has led to the development of new classes of transistors. It is difficult to classify transistors correctly because of the rich class of devices, so the classification of transistors is discussed below.

• Point contact transistors
• Junction transistor

Transistors can be divided into different ways based on semiconductors

• Germanium transistor
• Silicon transistor
• Transistors in polycrystalline
• Mon crystalline transistors
• Silicon carbide transistors.

There are again two types of junction transistors based on the nature of the structure

• A bipolar junction transistor (BJT)
• a field-effect transistor (FET)

This bi-polar junction transistor is again one of two types

• NPN transistor
• PNP transistors

Field-effect transistors are again one of two types

• Junction transistor
• Metal oxide semiconductor field-effect transistor (MOSFET)

The junction transistor is again one of the two types

• N channel
• P channel