Simple audio circuits

jojo December 2, 2012 9 Comments
This article is a compilation of the simple and popular audio circuits we have published over years in CircuitsToday. This list involves a collection of simple amplifier circuits that you can try at home and some other audio related circuits with specific applications.  Image Source 1. 150 Watt amplifier circuit – This circuit is the most popular amplifier we have ever published. It has received over 700+ comments and is still counting. This amplifier has been tested by many...
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Understanding the PN Junction

jojo July 21, 2014 30 Comments
Whenever someone decides to learn electronics, the first question that comes to his mind may be – “Where shall I begin?“. I would say, one shall begin at a junction 😉 the “pn junction“. We know semiconductor devices like transistors and diodes are the basic building units of any equipment that involves electronics, say tablet computers to the sophisticated MRI machines! How these basic units like transistors and diodes are formed ? or how are they made ? The...
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Delay using 8051 timer

admin November 28, 2012 9 Comments
Delay using 8051 timer.  The 8051 microcontroller has two independent 16 bit up counting timers named Timer 0 and Timer 1 and this article is about generating time delays using the 8051 timers. Generating delay using pure software loops have been already discussed here but such delays are poor in accuracy and cannot be used in sensitive applications. Delay using timer is the most accurate and surely the best method. A timer can be generalized as a multi-bit counter...
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The Best & Free Android Applications for the Electronics & Electrical Engineers

jojo November 28, 2012 11 Comments
The world around us is changing at a much faster pace than any one can anticipate. The world of “computing” has already seen great shifts from Desktops to Notebooks to Smartphones and Tablets. The coming decade will be more focused on mobile computing and cloud computing. Here in this article, I am listing some of the best and really useful applications released in Android market (aka Google Play), that comes handy for any one who is working in Electrical...
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How to debug in Keil Microvision

Nilay Banker November 21, 2012 4 Comments
In this article we will take a look at Debugging feature of Keil uVision. In Previous Article we had seen how to create project, hex file and building Project. Once you build your project and if you see 0 errors and 0 warnings you are half way through your project. Now what is debugging? Debugging is to identify and fix bugs in your project e.g. logical or synchronization problems in the code, or a design error in the hardware.First go...
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What is Image Processing?An Introduction to basics

Avaneet Ranjan November 21, 2012 3 Comments
Sight/vision is one of the greatest powers of a human being. Our eyes can tell us the shape, size, color of any and everything which comes in front of it.An Image is a 2 D light intensity function f(x,y). A digital image f(x,y) is discretized both in spatial coordinates and brightness.It can be considered as a matrix whose row, column indices specify a point in the image and the element value identifies the intensity value at that points. These...
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Software delay routine in 8051 microcontroller

admin November 16, 2012 3 Comments
Software delay routine in 8051 In an 8051 microcontroller, it requires 12  cycles of the processor clock for executing a single instruction cycle.  For an 8051 microcontroller clocked by a 12MHz crystal, the time taken for executing one instruction cycle is 1µS and it is according to the equation,  Time for 1 instruction cycle= 12 /12MHz = 1µS.  The shortest instructions will execute in 1µS and other instructions will take 2 or more micro seconds depending up on the...
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Raspberry Pi-Getting started with the revolutionary computer

jojo November 6, 2012 3 Comments
Are you hearing the name “Raspberry Pi” for the first time? Then you must really recheck your reading habits! I must say that you are not up to date with the latest happenings around the world 😉 Well, Raspberry Pi is nothing more than a small,customizable computer. When you read “computer“, dont think that its something like an Ipad or a Samsung Galaxy Note. Raspberry Pi is an educational product designed for students/hobbyists to learn computer easily.  It is available in...
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Getting Started with Keil uVision

Nilay Banker November 4, 2012 21 Comments
An Introduction to Keil MicroVision Embedded system means some combination of computer hardware and programmable software which is specially designed for a particular task like  displaying message on LCD. If you are still wondering about an embedded system, just take a look at these circuit applications using 8051 microcontroller. You can call these applications embedded systems as it involves hardware (8051 microcontroller) and software (the code written in assembly language). 1. Voltmeter using 8051 2. Thermometer using 8051 3....
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Random number generator using 8051

admin December 13, 2012 9 Comments
Random number generator using 8051. A  random number generator using 8051 that  displays a random number between 0 & 99 is shown in this article. The circuit it self is very simple and may not find any applications in serious embedded projects and this article is just an illustration. The circuit is based on AT89S51 microcontroller, two seven segment LED displays, two transistors and few passive components. Circuit diagram. The two seven segment LED displays are multiplexed together and...
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Digital thermometer using 8051

admin December 13, 2012 29 Comments
Thermometer using 8051. This article is about a simple 0-100°C digital thermometer with 1°C resolution using 8051. The circuit is based on LM35 analog temperature sensor, ADC0804 and AT89S51 microcontroller. LM35 is an analogue temperature sensor IC which can measure a temperature range of -55 to 150°C. Its output voltage varies 10mV per °C change in temperature. For example, if the temperature is 32°C, the output voltage will be 32 x 10mV = 320mV. ADC 0804 is used to convert...
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Most Popular Simple Electronic Circuits

jojo January 3, 2018 3 Comments
In this article we are attempting to list the most popular electronic circuits we have published over the last couple of years.  We know, its a little difficult task! First hurdle to cross is selecting the criteria to decide – “what makes a circuit popular ?“. Next hurdle is listing all of them in an ordered and categorized manner. Some circuits may seem so silly and simple for an experienced hobbyist/electronics geek, while some other circuits may seem so...
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Voltmeter using 8051

admin October 4, 2012 14 Comments
Voltmeter using 8051. A simple 0-5V voltmeter using 8051 is shown in this article. This digital voltmeter has a sensitivity of  200mV which is a bit low but this project is meant for demonstrating how an ADC and seven segment display can be interfaced to 8051 to obtain a digital readout of the input voltage. A 31/2 digit high end voltmeter will be added soon. ADC0804 is the ADC and AT89S51 is the controller used in this project. Before...
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AVR Microcontroller Tutorial – The complete guide to learn AVR

jojo September 29, 2012 5 Comments
We have developed a complete guide to learn AVR microcontroller – a tutorial which teaches the architecture,pin diagram,how to program an avr micro controller, how to work with ADC of avr, how to work with SPI of avr,interfacing LCD with avr, the avr gcc library, how to work with external interrupts, how to establish a USART communication etc. We have also developed a simple project to try your hands on – a frequency counter circuit built using Avr Atmega8....
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Control structures and statements in C and C++

jojo September 20, 2012 8 Comments
Control structures form the basic entities of a “structured programming language“. We all know languages like C/C++ or Java are all structured programming languages. Control structures are used to alter the flow of execution of the program.  Why do we need to alter the program flow ? The reason is “decision making“! In life, we may be given with a set of option like doing “Electronics” or “Computer science”. We do make a decision by analyzing certain conditions (like...
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Quick Sorting algorithm with example code in C/C++/Java languages

jojo September 18, 2012 No Comments
We have seen 3 simple sorting algorithms already 1) Bubble Sorting 2) Selection Sorting and finally Insertion sorting. All these algorithms were so simple to understand and were easy to implement as a program in C/C++ or even Java. But at the same time all 3 of them were too inefficient.  Their execution time was of the order of n*n, where n is the number of elements to be sorted. In practice, these simple sorting algorithms are seldom used. ...
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Insertion sorting algorithm with example in C/C++/Java languages

jojo September 17, 2012 No Comments
So far we have seen 2 sorting algorithms:- 1) Bubble sorting and 2) Selection sorting. Now in this article, we are analyzing insertion sort algorithm with its example code suitable for C/C++/Java programming languages. I recommend you go through above articles of Bubble sorting and Selection sorting before reading further.  Insertion sorting algorithm sorts one element at a time. It begins by sorting the first 2 elements in order. In the next step, it takes the third element and compares it...
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Bit rate Vs Baud rate – the common misconception

Anish September 17, 2012 17 Comments
The two most common/confused words in digital communication – Bit rate and Baud rate. Generally, communication is concerned with transmission of data. In digital communication, there are two entities that are needed to carry out communication – the data to be transmitted and the signal over which the data is transmitted. Now, we have two entities to be worried about – the data and the signal. The most common misconception is that most people think both travel at the...
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Selection Sort in C/C++/Java programming languages

jojo September 17, 2012 No Comments
In the previous article, we have analysed Bubble sort algorithm and it’s implementation in C programs. In this article we are going to see another sorting algorithm, named, Selection sorting. Just like “Bubble sort”, selection sort is also considered as an inefficient sorting algorithm. If you are curious to know the reason for this, please read the article about Bubble sort carefully. The number of comparisons involved in an average bubble sort is 0.5*(n*n-n). Same is the index for...
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Difference between Procedure Oriented(POP) and Object Oriented Programming(OOP)

jojo September 14, 2012 7 Comments
We all know there exist 2 approaches to write a program – 1) Procedure oriented programming (POP) and 2) Object oriented programming (OOP). You can write a program in either way but there are notable differences between both approaches. These 2 approaches are the result of software development evolution over many decades. Since the invention of computer, many approaches and methods have been tried to write a program. It includes methods like a) Top-Down programming b) Bottom-Up programming c)...
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How to recover/reset admin username and password of Vbulletin forum software

jojo September 11, 2012 2 Comments
This article is a little off topic as it is not related to electronics! However I thought this would be useful for some one who manages a Vbulletin forum software. For those who find the name “Vbulletin” alien, it’s a forum management software. We use it to power our CircuitsToday-Forums. Recently we lost access to our “administrator” account of our forum software! There had been no way we could access the admin account and all attempts to retrieve password...
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Interfacing ADC to 8051

admin September 6, 2012 5 Comments
ADC (Analog to digital converter) forms a very essential part in many embedded projects and this  article is about interfacing an ADC to 8051 embedded controller. ADC 0804 is the ADC used here and before going through the interfacing  procedure, we must neatly understand how the ADC 0804 works. ADC 0804. ADC0804 is an 8 bit successive approximation analogue to digital converter from National semiconductors. The features of ADC0804 are  differential analogue voltage inputs, 0-5V input voltage range, no zero...
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How to work with the ADC unit of an AVR Micro-controller

Mathew Kevin July 9, 2017 3 Comments
Introduction                 The first step to digital signal processing is to convert a signal into digital data, and here the Analog to Digital Converter devices comes into action. Some of the AVR micro controllers include ADC unit in their features. This is a very useful unit for measurement related applications. The ADC used in AVR micro controllers are of successive approximation converter type. Read the Wikipedia article on SAR type ADC here. And you can read the Circuitstoday article...
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Working with External Interrupts in AVR micro controller

Mathew Kevin July 10, 2017 3 Comments
Introduction to Interrupts                 Although micro controllers can accept inputs from Digital I/O Ports,interrupts are preferred for accepting inputs generated by external events. This is mainly because of the less attention required for an interrupt based program. An Interrupt Event directs the flow of program execution to a totally independent piece of code, known as “Interrupt Sub-Routine”. There are many sources of Interrupts that are available for a micro controller. Most of them are generated by the internal modules...
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