• Usha Saha

What is electronics?

Updated: Dec 1, 2020

Electronics is the science that deals with the electrical devices and circuit that operate by controlling the flow of electrons or other electrically charged particles. In simple words, electronics is the science of the motion of charges in a gas, vacuum, or semiconductor. This article covers the complete overview of the electronic system its classifications, applications, and usages.


The electronic system is basically classified into two categories.

1: Digital system

2: Analog system

Classification of Electronics System

An Analog system is a system in which voltage and current vary continuously throughout the given range and can take any value. Whereas in a digital system the voltage levels have a finite number of distinct values.

Digital Electronics

Digital circuits are also called switching circuits because of the instantaneous switching of values from one to another(there is only two value and they are zero '0' and one'1'). They are also called logic circuits because there is always a logic behind every digital circuit.


Representation Of a Digital Signal


Digital Circuit Composition


Digital Signal Composition

Logic Gates:- It comprises of basic gates which are NOT Gate, AND Gate, and OR Gate. Universal gates that are NAND and NOR gate, these are universal gate because they can perform all the three basic operations of NOT, AND, and OR. Special purpose gates include the Exclusive-OR gate(EX-OR) and the Exclusive-NOR gate(EX-NOR). Logic gates are the fundamental building block of any digital system.


Combinational Logic Circuits:- Combinational Logic Circuits as the name suggest consist of a combination of logic gates whose output at any instant of time is calculated by the present combination of inputs only. Combinational circuits, therefore, are also called a #memoryless system as the output is only dependent on the present values of input.


The arithmetic circuit is designed to carry out arithmetic operations like addition and subtraction via Adders and Subtractors. There are other operators also like Binary Parallel Adder, Look-ahead Carry Adder, etc.

Non-arithmetic Circuits as the name signifies perform non-arithmetic operations. Some non-arithmetic operators are Code convertor, Magnitude comparator. Multiplexers (MUX) is the most widely used circuit in designing purposes. A multiplexer is also a #universal logic gate. Demultiplexer(DEMUX) operates exactly the opposite of MUX.


Sequential Logic Circuits:- In sequential Circuits, the output at any instant of time depends on the present as well as past input variables. Therefore sequential Circuits are called #memory circuits as memory is required to store the past inputs.


Latches and Flip-Flops:- Flip-Flops are the basic building block of any sequential circuit, it has two stable states therefore also known as a #bistable multivibrator. The simplest form of Flip-Flop is called Latch which is used for storing information. The major difference between a Flip-Flop and a Latch is the method used for changing the states.


Registers and Counters:- A register is a digital circuit having two basic functions that are storage and data movement. It is a group of Flip-Flop connected to perform various operations. There are four types of shift registers namely SISO, SIPO, PIPO, and PISO.

The counter is a digital circuit that is used to count the number of occurrences in the input. It consists of flip-flops cascaded inside. Counters are of two types Synchronous and Asynchronous counters.


Advantages of Digital System:-

1:- The digital having two input and output levels, ON and OFF, HIGH and LOW make the design easier.

2:- Digital systems can be expanded easily to handle more digits by simply adding more switching circuits.

3:- Information storage is easy as there are a variety of semiconductor memories with a large capacity for storing data.

4:- Digital systems are less affected by noise.


Limitation of Digital System:- The real world is mainly analog also human does not understand the digital data.


Analog Electronics

The Analog signal is similar to physical signals.


Analog Signal Representation

Diode:- Diode is the simplest circuit element in an analog circuit, it is a two-terminal device that allows current only in one direction. A diode is used as a major element in low voltage rectifiers construction. The low voltage rectifiers are Half-wave rectifier, Full-wave rectifier, Centre tapped full-wave rectifier, and Bridge rectifier.


Bipolar junction transistor(BJT):- The name BJT signifies, B for #bipolar that is it allows the flow of both electrons and holes, J-for junction and T- for transfer+resistor. It is a three-terminal device used for amplification of week signals, in switching operations, etc.


NPN and PNP Transistor Representation

Filed effect transistor(FET):- FET is a #unipolar device due to this it allows the flow of current only due to majority carrier. There are two general categories of FET. First is JFET(Junction Field Effect Transistor) and the second is MESFET(Metal Semiconductor Field Effect Transistor). In JFET and MESFET the leakage current is high, in order to reduce it another type of FET is used namely MOSFET(Metal Oxide Semiconductor Field Effect Transistor).


The advantages of an analog circuit are that the majority of signal in the real world is analog so these signals can be directly used in analog circuits whereas the digital signals require conversion of digital to analog and vice versa.

Additional information:- Advanced electronics is another diverse category of electronics that deals with Integrated circuit technology (IC) design and fabrication which is capable of producing circuits that contain millions of components in a very small space.


See Also

Analog vs Digital

N-MOS, P-MOS & C-MOS Transistors


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