Digital electronics or digital circuits are a part of electronics that operates on digital signals. It is a branch of electronics that deals with boolean algebra. Boolean Algebra contains two signal level codes 0 or 1(Binary). Boolean Algebra is employed to research and simplify digital circuits. Boolean logic contains basic operators like AND, OR, and NOT, etc. Operations are represented by ‘.’ for AND, ‘+’ for OR. Boolean logic is further represented by logic gates. Logic Gates is a device that implements a boolean function. A logic gate is the building block of a digital circuit.False represents ‘0’ and true represents ‘1’.The basic logic Gates are categorized into seven types: AND, OR, NOT, NOR, NAND, EXNOR, EXOR.

GATE SYMBOL EQUATION

AND Q=A.B

OR Q=A+B

NOT Q=A` `

`NOR Q=(A+B)`

NAND Q=(AB)`

EXOR Q=A`B+AB`

EXNOR Q=(AB`+A`

B)`

**AND gate(.) **– The AND gate gives an output of 1 if both the two inputs are 1, it gives 0 otherwise.

**OR gate(+) **– The OR circuit gives an output of 1 if either of the 2 inputs is 1, it gives 0 otherwise.

**NOT gate(‘) **– The NOT gate gives an output of 1 input is 0 and vice-versa.

**XOR gate **– The X-OR circuit gives an output of 1 if either both inputs are different, it gives 0 if they’re the same.

**NAND gate-** The NAND circuit (negated AND) gives an output of 0 if both inputs are 1, it gives 1 otherwise.

**NOR gate-** The NOR gate (negated OR) gives an output of 1 if both inputs are 0, it gives 1 otherwise.

**XNOR gate-** The XNOR gate (negated XOR) gives an output of 1 both inputs are the same and 0 if both are different. Out of the seven logic gates discussed above, NAND and NOR also are referred to as universal gates since they will be wont to implement any digital circuit without using the other gate. this suggests that each gate is often created by NAND or NOR gates only. These logic gates are further represented within the sort of truth table. A truth table shows each possible combinations to the gate OR circuit with resultant output counting on a combination of input.

## Why digital?

1)Data can be stored.

2)Data can be used in calculations.

3)used in display technologies.

4)Systems can be programmed

Electronic and Digital systems may use a variety of different number systems, (e.g. Decimal, Hexadecimal, Octal, Binary).

Digital Electronics uses a series of 1’s and 0’s to store and communicate information. Digital electronics is the foundation of modern computers. Digital Counters: A counter is a device which stores the number of times a particular event or process has occurred. In digital electronics, they are used for counting purposes. It is of two types: 1)Asynchronous 2)Synchronous.

In today’s hi-tech world everyone has access to state of art of security systems .one of the latest trends is a digital safe locker. These lockers are electronic safe locking systems that operate as per signals received in the input keyboard. For example, digital-based door lock systems for auto door opening and shutting, token-based-digital-identity devices are all supported digital technology. These locking systems are controlled by a keypad and are installed at the side hedge of the door.

Digital circuits are utilized in mobile phones, computers, and lots of other products of daily use. The most revolutionary advantage of digital electronics is decreased in size and improvement in technology. As we know Digital Electronics is one of the important subjects, most students of Computer or electronics background have a basic understanding of digital electronics.

Digital Electronics has a number of applications in so many different fields. Ranging from something as simple as the Display of your digital watch or the Count-down timer which you see at traffic signals.LCD/LED TV, TATA Sky, any kind of remote control you use, your mobile/smartphone, tablet, computer, keyboard, mouse, the speed/distance meter on your bike/car, various control of the car, ATM machines, credit /debit cards, the telephone exchange of your town/city all of them are heavily benefitted by Digital Technology. These days it is difficult to find an application that is not using Digital. Almost every other gadget you use these days is an application of Digital Electronics.