Working Of Electric Cars

john January 13, 2010 23 Comments
Studies have shown that the past decade had a rise in the number of cars to almost 500% than the previous one! This rise in cars has also been a major cause for the vast environmental pollution throughout the world. The introduction of electric cars has proved that they are very much environmental friendly and less pollute compared to gas cars. There has been a rapid increase in the sale of electric cars for the past few years. Comparison...
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Frequency to voltage converter using LM331

jacky August 13, 2017 32 Comments
Making a frequency to voltage converter – All you need to know Description LM331 is basically a precision voltage to frequency converter from National Semiconductors. The IC has a hand full of applications like analog to digital conversion, long term integration, voltage to frequency conversion, frequency to voltage conversion. Wide dynamic range and excellent linearity make the IC well suitable for the applications mentioned above. Here the LM331 is wired as a frequency to voltage converter which converts the...
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Speed control for PCB drill

john January 12, 2010 11 Comments
Description. Here is a simple circuit for controlling the speed of DC operated PCB drills. The heart of this circuit is the ICLM3578 which is a very efficient integrated switching regulator that can be used for applications like this. The LM3578 has separate inverting and non inverting feedback inputs (pin1 and pin2), 1V internal reference voltage source and a built in oscillator circuit. The IC can be configured to obtain up to 90% duty cycle. In the circuit, capacitor...
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Subwoofer filter

john April 7, 2010 46 Comments
Description. Here is the circuit diagram of an opamp based subwoofer filter. Audio frequencies below 200Hz are considered to be in the subwoofer range. So a subwoofer filter will be essentially a low pass filter with a cut off frequency of 200Hz.The working of this straight forward circuit is as follows. The left channel of the audio source is connected to the non-inverting input of opamp U1 which is wired as a buffer. Opamps U2 and U3 forms a...
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MOS Transistors – Operation

john January 12, 2010 1 Comment
The bipolar junction transistor is the one which amplifies a small change in input current to produce a large change in output current. Another type of transistor, called a field effect transistor (FET), converts a change in input voltage into a change in output current and thus the gain of an FET is measured by its transconductance, defined as the ratio of change in output current to change in input voltage. The voltage is applied to the input terminal...
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Add/Replace RAM to your Laptop easily!

john January 12, 2010 No Comments
Nowadays desktop PC’s are getting diminished due to the high demand for laptops. Though both desktops and laptops have the same specifications, the way they are put together is what makes them different. You can carry your laptops wherever you like and can also be run on battery unlike a desktop computer (though it runs on UPS, it does not stand for a long time compared to laptop). They are smaller in size and also thin and lightweight. Desktop...
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Voice recorder/playback circuit

john April 7, 2010 11 Comments
Description. This circuit is designed in response to a request made by Mr Vignesh. What he requested was a circuit for recording and playing voice. I think this circuit is enough for the purpose. This circuit is based on the IC ISD1020A from ISD. The ISD1020A is a CMOS single chip record/playback device. The chip can record voice for 20seconds and has many features like automatic gain control, anti aliasing filter, built in audio amplifier and smoothing filter. The...
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Working of an Inductor

john March 12, 2010 13 Comments
Working Of Inductors I have explained many articles on various electronic circuits, which shows applications of Inductors. But I have not explained the proper working of inductor till now. Inductors are used in many analog circuits and are also used along with capacitors for forming filter circuits and thus signal processing. They are also used in Switched Mode Power Supplies (SMPS), oscillators, transmitters, receivers, voltage regulators and also for over voltage protection. What is an Inductor? An Inductor, also...
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LED based transistor tester

john March 22, 2011 18 Comments
Description. Here is the circuit of a very simple transistor tester which used two LEDs for displaying the condition of a transistor. Both PNP as well as NPN transistors can be tested using this circuit. Quad 2 input CMOS NAND gate IC CD4011B is the heart of the circuit. Out of the four NAND gates inside the IC, only three are used here and they are used as NOT gates by shorting their input terminals. Gates U1a, U1b, resistor...
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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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