Liquid Crystal Displays (LCD) – Working

john August 10, 2017 37 Comments
We always use devices made up of Liquid Crystal Displays (LCDs) like computers, digital watches and also DVD and CD players. They have become very common and have taken a giant leap in the screen industry by clearly replacing the use of Cathode Ray Tubes (CRT). CRT draws more power than LCD and are also bigger and heavier. All of us have seen an LCD, but no one knows the exact working of it. Let us take a look...
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Digital compass circuit

john January 6, 2010 13 Comments
Description. Here is the circuit diagram of a very simple and accurate electronic compass using the 1490 digital compass from Dinsmore. The 1490 digital compass is a solid state Hall Effect device which is sensitive to detect the Earth’s magnetic field. The sensor is internally damped to simulate the performance of an ordinary compass. The circuit shown here is the simplest one that can be built around this sensor. The sensor has 12 pins at the bottom which are...
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Working of Speakers

john July 25, 2011 2 Comments
We have always shown keen interest in buying the best electronic stuffs like CD’s, tapes and also computers. No one has bothered much to know about the quality of the speakers that bring the ultimate output. Even if any high end amplifier and other devices are used, it will all become a waste if the proper loud speaker is not used to present the output. The speaker is mainly responsible for changing the electronic signals that are produced by...
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Pocket headphone amplifier

john April 7, 2010 19 Comments
Description. Here I present a very simple and powerful headphone amplifier using OPA134. In addition to the IC OPA134, the circuit uses only few passive components and can easily generate a lot of sound from even the most inefficient headphones and there will be no compromise for the quality. OPA134 is low noise, low distortion operational amplifier from BURR-BROWN semiconductors and it is exclusively meant for audio applications. The FET based input stage provides the IC with high input...
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Digital voltmeter using ICL7107

john February 2, 2011 83 Comments
Description. The circuit given here is of a very useful and accurate digital voltmeter with LED display using the ICL7107 from Intersil. The ICL7107 is a high performance, low power, 3.5 digit analog to digital converter. The IC includes internal circuitry for seven segment decoders, display drivers, reference voltage source and a clock. The power dissipation is less than 10mW and the display stability is very high. The working of this electronic circuit is very simple. The voltage to...
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Bluetooth Technology

john December 16, 2009 8 Comments
As innovative ideas are introduced along with the technological boom, our communication methods are becoming more and more easier. We have seen devices communicating each other with the help of wires, cables, radio-signals, wireless and also infrared signals. Apart from these physical connections, there are also some protocols (a set of commands and responses) that should be obeyed by the devices so as to stream their data. These protocols include The amount of data that should be sent at...
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Telephone operated remote

john December 15, 2009 33 Comments
Description. The circuit given below is of a telephone operated DTMF remote. The circuit can be used to switch up to 9 devices using the keys 0 to 9 of the telephone. Digit 0 is used to switch the telephone system between remote switching mode and normal conversation mode. IC KT3170 (DTMF to BCD decoder) is used to decode the DTMF signals transmitted over the telephone line to corresponding BCD format. IC 74154 ( 4 to 16 demultiplexer) and...
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Working of a Capacitor

john October 25, 2013 12 Comments
Definition A capacitor is an electronic device that is used to store electrical energy. They are only used to store the electrons and they are not capable of producing them. Invention of the Capacitor There are many stories behind the invention of the capacitor. A German scientist named Ewald Georg von Kleist was known to invent the capacitor in November 1745. But, he did not have any detailed notes or records of his invention. So, he was given the...
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Stepper motor driver using MC3479

john December 14, 2009 4 Comments
Description. The circuit diagram given here is of a stepper motor driver using MC3479 from Motorola. The MC3479 is specifically designed for driving a 2 phase stepper motor in bipolar mode and is available in standard DIP and surface mount packages.The IC is compatible to TTL and CMOS inputs and has selectable HIGH/LOW output impedance. The output can deliver up to 350mA each of two coils of a 2 phase stepper motor. The state change of the output occurs...
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How Global Positioning System (GPS) works?

john June 5, 2012 6 Comments
Introduction Global Positioning System (GPS), has found itself as a gateway for the cutting edge technology for this century. It was designed and developed by USA during the late 19th century after recognizing its importance in military applications. Due to its accurate positioning capabilities and navigation and timing services it was later open for civilian uses as well.   Working of GPS A GPS system consists of •             A GPS enabled product like a GPS phone or a GPS...
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FM Radio jammer

john January 13, 2010 117 Comments
Description. Circuit shown here can be used to jam FM radios in its vicinity. The circuit is nothing but a classic single transistor oscillator operating in the VHF region. Working principle of the circuit is very simple and straight forward. Powerful VHF oscillations from the circuit will interfere with the FM signals to nullify it. Jammer circuits like this are illegal in many countries and you must assemble this circuit on your own responsibility. This circuit is intended only...
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2 km FM transmitter

john January 23, 2018 454 Comments
Description. With a matching antenna, the FM transmitter circuit shown here can transmit signals up to a range of 2 kilo meters. The transistor Q1 and Q2 forms a classic high sensitive preamplifier stage. The audio signal to be transmitted is coupled to the base of Q1 through capacitor C2. R1, R3, R4, R6, R5 and R9 are the biasing resistors for the preamplifier stage comprising of Q1 and Q2. Transistor Q3 performs the collective job of oscillator, mixer...
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Air Bullet Technology to cool overheated LED’s

john February 24, 2011 No Comments
  As we all know Light Emitting Diodes(LED’s), are used in a wide range of applications  like indicators, long-lasting source of illumination in sensors, home and also industrial applications. They are known for their less heat dissipation and also as an electricity saver. If our usual bulbs like incandescent and fluorescent bulbs  are to be replaced by LED’s the latter must be more larger as well as powerful than the former. But for this, the heat dissipated by the...
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24V flasher circuit

john March 3, 2010 11 Comments
Description. The circuit shown here works from 24V DC and can flash two 24V bulbs alternatively. The circuit is nothing but an astable multivibrator operating at 1Hz and 50% duty cycle. The lamp to be flashed is connected in place of the collector resistor (Rc) of a typical design. 2N3055 transistors which are well known for their ruggedness are used here. They can handle collector currents up to 10A. So a wide range of lamps (in terms of wattage)...
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Powerful LED flasher

john December 10, 2009 2 Comments
Description. This is the circuit diagram a powerful LED flasher. High power LEDs are very common in the market now and a 1W high power LED is used here. Transistors Q1 and Q2 are wired as an oscillator which produces positive pulses of width 20ms @ ½ Hz. Transistor Q3 and MOSFET Q4 inverts this pulse and MOSFET Q5 drives the LED D1. Circuit diagram . Notes. LED D1 is a 1W high power LED. Capacitors C1 and C2...
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Top 5 Mobiles of 2009

john January 17, 2011 3 Comments
As we are coming towards the end of 2009, it is time to declare the detailed list of the best mobiles of 2009. The list contains a brief review of some of the best featured as well as best selling mobiles throughout the world. Apple i-phone 3GS – 32 GB (AT &T) The mobile industry saw a mega boom with the release of the Apple i-phone. Two years later they decided to release the Apple i-phone 3GS with more...
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Battery eliminator circuit

john December 14, 2009 25 Comments
Description. Here is the circuit diagram of a battery eliminator circuit that can be used as a replacement for 9V PP3 batteries. The circuit given here can be used to power any device that operates from a 9V battery. The transformer T1 steps down the mains voltage and bridge D1 performs the job of rectification. Capacitor C1 is a filter. IC LM317T is the regulator here. The value of R1, R2 and R3 are so selected that the output...
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Comparison Between Half-Wave and Full-Wave Voltage Doublers

john October 19, 2009 No Comments
Half-Wave Voltage Doubler Availability of common point between input and output lines for earthing – Yes, available Ripple Content – High Ripple Frequency – Supply Frequency Voltage Regulation – Poor Maximum Voltage Across Each Capacitor – 2 Vs max PIV Rating Of Each Diode – 2 Vs max Full-Wave Voltage Doubler Availability of common point between input and output lines for earthing – No, not available Ripple Content – Low Ripple Frequency – Twice Supply Frequency Voltage Regulation –...
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Voltage Multipliers

john October 19, 2009 7 Comments
Voltage multiplier is a modified capacitor filter circuit that delivers a dc voltage twice or rnore times of the peak value (amplitude) of the input ac voltage. Such power supplies are used for high-voltage and low-current devices such as cathode-ray tubes (the picture tubes in TV receivers, oscilloscopes and computer display). Here we will consider half-wave voltage doubler, full-wave voltage doubler and voltage tripler and quadrupler. Half-Wave Voltage Doubler The circuit of a half-wave voltage doubler is given in...
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Diode Clamping Circuits

john January 23, 2018 26 Comments
Diode Clamping Circuit In this article, the working of a clamping circuit is explained. The working of different clamping circuits like positive and negative clamper, with circuit diagrams and waveforms are given below. Related Articles CLIPPING CIRCUITS DIODE CLIPPERS DIODE CLIPPERS – APPLICATIONS TRANSISTOR CLIPPING CIRCUITS A clamping circuit is used to place either the positive or negative peak of a signal at a desired level. The dc component is simply added or subtracted to/from the input signal. The...
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Transistor Clipping Circuits

john March 28, 2011 4 Comments
Transistor Clipping Circuits In this article, the transistor clipping circuits is explained in detail along with the circuit diagrams and waveforms. The transistor clipper circuit waveform for ramp and sinusoidal input is given below. Related Articles CLIPPING CIRCUITS DIODE CLIPPERS DIODE CLIPPERS – APPLICATIONS DIODE CLAMPING CIRCUITS The transistor has two types of linearities —One linearity happens when the transistor passes from cut-in region to the active region. The other linearity occurs when the transistor passes from  the active...
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Diode Clippers – Applications

john February 21, 2011 1 Comment
Application of Diode Clipper In this article, all the applications of diode clipper is explained in detail. Related Articles CLIPPING CIRCUITS DIODE CLIPPERS TRANSISTOR CLIPPING CIRCUITS DIODE CLAMPING CIRCUITS There are numerous applications for diode clippers. They find wide application in television receiver for separating synchronizing signals from composite picture signals and also in television transmitters at the time of processing the picture signals. They are also employed for different wave generation such as trapezoidal, square or rectangular waves....
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Diode Clippers – An overview of Clipping Circuits

john April 14, 2011 77 Comments
Diode Clippers – A study of  various Clipping Circuits This article explains the working of different diode clipper circuits like Positive and Negative Diode Clippers, Biased Clipper circuit, and Combinational Clipper Circuit with the help of circuit diagrams and waveforms. The basic components required for a clipping circuit are – an ideal diode and a resistor. In order to fix the clipping level to the desired amount, a dc battery must also be included.  When the diode is forward...
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Clipping Circuits

john February 21, 2011 6 Comments
Clipping Circuits This article defines the basics of Clipper Circuit, classifications according to the devices used, biasing, configuration, level used and so on. Related Articles TRANSISTOR CLIPPING CIRCUITS DIODE CLIPPERS DIODE CLIPPERS – APPLICATIONS DIODE CLAMPING CIRCUITS Clipping circuit is a wave-shaping circuit, and is used to either remove or clip a portion of the applied wave in order to control the shape of the output waveform. One of the most basic clipping circuit is the half-wave rectifier. A...
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Sweep Frequency Generator

john March 28, 2011 3 Comments
Sweep-Frequency Generator The working of a sweep-frequency generator is explained in the article below. The working and block diagram of an electronically tuned sweep frequency generator and its different parameters are also explained. Related Article SIGNAL GENERATORS A sweep frequency generator is a type of signal generator that is used to generate a sinusoidal output. Such an output will have its frequency automatically varied or swept between two selected frequencies. One complete cycle of the frequency variation is called...
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