Definition: Programmable Logic Array, abbreviated as PLA is a programmable logic device having programmable AND gates and OR gates. These devices are basically programmed to implement the Boolean functions. The fundamental components of PLAs are input buffer, programmable AND gate matrix and programmable OR gate matrix. PLA allows the implementation of any random boolean function present in SOP form using programmable technique. Components of PLA Input Buffer: Basically buffers at the … [Read more...] about Programmable Logic Array (PLA)

# Digital Electronics

## Shift Register

Definition: A shift register is a sequential logic circuit that acts as a unit to store and transfer binary data. Basically shift registers are bidirectional FIFO circuit, that shifts every single bit of the data present in its input towards its output on each clock pulse. We know registers are the circuits constructed using flip-flops for storing binary data. One-bit of data is stored by each flip-flop at a time. So, the storage of multiple bits of data requires multiple flip-flops. Thus … [Read more...] about Shift Register

## Digital Comparator – Magnitude and Identity Comparator

Definition: A Digital Comparator is a combinational logic circuit that is used for comparison of two binary values. Basically it generates the desired signal (either low or high) at the output when compares two digital values provided at its input. We all know that combinational circuits (like adder and subtractor) produce addition and subtraction of binary values present at the input terminals. But, along with addition and subtraction, some applications require a comparison of two values … [Read more...] about Digital Comparator – Magnitude and Identity Comparator

## Synchronous Counter

Definition: The synchronous counter is a type of counter in which the clock signal is simultaneously provided to each flip-flop present in the counter circuit. More specifically, we can say that each flip-flop is triggered in synchronism with the clock input. Unlike asynchronous counter where separate clock pulses are used to trigger the flip-flop, all the flip-flops in synchronous counters are triggered using a single clock pulse. We know designing an asynchronous counter is easy then … [Read more...] about Synchronous Counter

## Asynchronous Counter

Definition: Asynchronous counters are those counters which do not operate on simultaneous clocking. In asynchronous counter, only the first flip-flop is externally clocked using clock pulse while the clock input for the successive flip-flops will be the output from a previous flip-flop. This means that only a single clock pulse is not driving all the flip-flops in the arrangement of the counter. Asynchronous counters are also known as ripple counters and are formed by the successive … [Read more...] about Asynchronous Counter

## Logic gates

Definition: Logic gates are basically electronic circuits that perform logical functions such as addition, subtraction, multiplication etc. For any digital system, it acts as an elemental building block and is able to make logical decisions. It performs logical functions in order to produce an output when two or more inputs are applied. Basically, the operation of logic gates is represented by algebraic expressions. To form a big logic network sometimes, the output of a gate is fed to the … [Read more...] about Logic gates

## Half Subtractor

Definition: The Half Subtractor is a digital circuit which processes the subtraction of two 1-bit numbers. In this, the two numbers involved are termed as subtrahend and minuend. In the subtraction procedure, the subtrahend will be subtracted from minuend. The circuit of Half subtractor consists of two inputs and two outputs. The inputs of the half subtractor circuit will be subtrahend and minuend. On the other hand, the output will be the difference and the borrow. The word “HALF” before the … [Read more...] about Half Subtractor

## Parallel Binary Adder

Definition: The Parallel binary adder is a combinational circuit consists of various full adders in parallel structure so that when more than 1-bit numbers are to be added, then there can be full adder for every column for the addition. The number of full adders in a parallel binary adder depends on the number of bits present in the number for the addition. If 4-bits numbers are to be added, then there will be 4-full adder in the parallel binary adder. The parallel binary adder can be … [Read more...] about Parallel Binary Adder

## Half Adder

Definition: Half Adder is the digital circuit which can generate the result of the addition of two 1-bit numbers. It consists of two input terminal through which 1-bit numbers can be given for processing. After this, the half adder generates the sum of the numbers and carry if present. It is very easy to guess the working of the adder just by its name. This is because the word adder consists of keyword “ADD” which means to add any numbers. But what does this keyword “HALF” signifies. You … [Read more...] about Half Adder

## Demultiplexer

Definition: Demultiplexer performs the reverse operation of the multiplexer i.e. it takes a single output and can guide that single output through many outputs. The output to which the input signal is to be passed is decided by the control logic. The control logic can be manipulated by changing the value of the control signal. Thus, it is termed as the demultiplexer as it takes one input and generates several outputs. There can be various types of demultiplexer circuits depending on the … [Read more...] about Demultiplexer