Ashutosh Bhatt

Operating Systems have developed a lot in last 15 years. Starting from black and white phones to recent smart phones or mini computers, mobile OS has come far away. Especially for smart phones, Mobile OS has greatly evolved from Palm OS in 1996 to Windows pocket PC in 2000 then to Blackberry OS and Android. Android is a powerful Operating System supporting a large number of applications in Smart Phones. Android is a software bunch comprising not only operating system but also middleware and key applications. Android Inc was founded in Palo Alto of California, U.S. by Andy Rubin, Rich miner, Nick sears and Chris White in 2003. Later Android Inc. was acquired by Google in 2005.

Everyone must be familiar with the term – Switched Mode Power Supply or SMPS. Yes, they are used in every personal computer. In fact, the Switched Mode Power Supply is widely used with many other devices. Once it is understood that what SMPS actually is, its countless applications can be easily imagined.  An SMPS is used for converting the electronic power supply efficiently. Any SMPS has some storage components which store electrical energy to supply to the load device and some switching components which turn on and off at high frequencies charging and discharging the storage components.

 UM 3561 is an excellent Siren generator IC widely used in Toy applications and Surveillance systems to generate different tones. It a ROM (Read Only Memory) IC which can be operated in 2 pen cells and it functions normally down to 2.4 volts. Using only a few components, it is very easy to construct a…

 Fig. 1: Image of a Digital Panel Voltmeter  With a single IC L 7107, you can make a 4 digit voltmeter that can show 0-2000 voltsthrough seven segment display. The circuit is low component one and the reading is reliable and accurate. This circuit is used in digital panel meters to give alpha numerical display. Fig. 2:…

Electrons are invisible to human eye then how can we see the electronic smog existing in our home. Is there any method to see them? Impossible, the only method is to capture the energy from it to activate a circuit for giving a visual indication. When you sit in front of a computer or television,…

This Battery charger can replenish any kind of 12 V Inverter battery or Car battery and keep it in top condition. The charger never allows the battery to Over charge or Deep discharge. It automatically charges the battery when its terminal voltage drops below 12 volts and switch off the charging process when the terminal…

  Frequency modulation (FM) is a technique in which the frequency of a transmitted waveform is varied according to the variations in the message wave. The FM is a very popular technique since they are widely used by the FM radio stations. The main reason behind using the FM modulations by the radio stations is…

  The simple pulse modulation technique called Pulse Amplitude Modulation (PAM) proved to be more power efficient than the PWM and consumes constant power for individual pulses like PPM. In PAM the amplitude of the individual pulses are varied according to the amplitude of the modulating signals. The PAM modulator and demodulator circuits simple compared…

  The electronic circuits like amplifiers, modulators etc. have a particular range at which they can accept the input signals. Any signals which have amplitude higher than this particular rage can cause distortion in the output of the circuit or may even cause damage to the circuit components itself. Since most of the devices works…

Most of the electronic devices work on a single positive power supply except few like op-amps, oscillators etc. Majority of the amplifiers circuits or amplifiers ICs are also works on positive power supply. Such kind of devices can operate only with input signals having only positive voltages. Devices like amplifiers, modulators, demodulators etc. are supposed to work with natural signals as input. Since the natural signals like sine wave, audio signals etc. has both positive and negative cycles they have to be modified in such a way the single supply electronic circuits can operate them. Clamping is the common technique that is applied on the input signals to modify them so that the circuits can process the entire signal without losing either positive or negative half. In this method the entire waveform is shifted to positive of negative voltage side hence making them single polarity varying voltage.  

Call it an effort of human mind or a miracle from human heart. But this is all happening with technology. We land in an era where everything that can be possibly thought, can also be practically put into. And that too quite reasonably..!! Just move the hand or walk your fingers over a thing and it works. Yes, it is the interactive gesture based technology I am talking about.  A device which works on touchscreen technology is coined as Touchscreen. A touchscreen is an electronic visual display capable of ‘detecting’ and effectively ‘locating’ a touch over its display area. It is sensitive to the touch of a human finger, hand, pointed finger nail and passive objects like stylus. Users can simply move things on the screen, scroll them, make them bigger and many more. 

One of the major problems that is to be solved in an electronic circuit design is the production of low voltage DC power supply from AC to power the circuit. [[wysiwyg_imageupload::]]The conventional method is the use of a step-down transformer to reduce the 230 V AC to a desired level of low voltage AC. The most suitable and low cost method is the use of aVoltage Dropping Capacitor in series with the phase line. Selection of the Dropping capacitor and the circuit design requires some technical knowledge and practical experience to get the desired voltage and current.

 Here is a simple circuit to protect TV from high voltage spikes during lightning or a power surge in the cable. It can be incorporated in the Coaxial cable of TV Antenna or Set top box. It uses a GDT and Safety capacitor to provide protection from high voltage spikes. The same circuit can also…

Some Microcontroller based Laboratory instruments such as Digital balance, pH Meter etc have rechargeable battery inside. This inbuilt battery should be properly charged for the error free operation of these instruments. If the instrument is not using (or charging) for long time, its inbuilt battery will be destroyed permanently. This charger timer circuit helps to keep…

The conventional mechanical energy meter is based on the phenomenon of “Magnetic Induction”. It has a rotating aluminium Wheel called Ferriwheel and [[wysiwyg_imageupload::]]many toothed wheels. Based on the flow of current, the Ferriwheel rotates which makes rotation of other wheels. This will be converted into corresponding measurements in the display section. Since many mechanical parts are involved, mechanical defects and breakdown are common. More over chances of manipulation and current theft will be higher.Electronic Energy Meter is based on Digital Micro Technology (DMT) and uses no moving parts. So the EEM is known as “Static Energy Meter” In EEM the accurate functioning is controlled by a specially designed IC called ASIC (Application Specified Integrated Circuit). ASIC is constructed only for specific applications using Embedded System Technology. Similar ASIC are now used in Washing Machines, Air Conditioners, Automobiles, Digital Camera etc. 

 Op-amp 741 is a very well-known as well as very usable IC in many of the projects like amplifier circuits, voltage follower circuits, current to voltage changer or voltage to current changer and many more other applications. So for the proper working circuit it is highly necessary that your op-amp works correctly. So here the circuit that will help you to check whether your op-amp is in good condition or it is faulty.

Principle behind Circuit- This circuit is constructed with the help of much known IC NE555. In this circuit this IC work like a comparator. Pin 6 of the IC is lined with positive power supply. When pin 2 is less than 1/3 of the applied voltage output at pin 3 is high. Similarly the output…

Principle behind E-Cricket Circuit- This circuit is mainly for cricket lovers who watch cricket game and want to play, but unable to play due to their phatic schedule or any reasons. E-Cricket circuit shows various stages of cricket like out, six and many more with the help of various LED’s. At the time when S1…

FSK means Frequency Shift Keying. It’s one of the Modulation Scheme used to Transmit Digital Data using High Frequency carrier signal. In this Modulation Scheme bit 1 is transmitted using one carrier signal and bit 0 is transmitted using another carrier signal like·         Bit 1 (logic high) is Transmitted using Carrier Frequency Fc1·         Bit 0 (logic low) is Transmitted using Carrier Frequency Fc2It means Series of bits (bit stream) are transmitted with two different carrier signals used for bit 1 and bit 0.  

8.3) Voltage follower Voltage follower is a negative feedback op-amp amplifier circuit. It acts like emitter follower configuration of transistor based amplifiers. They provide unity gain to the applied input signals. Unity gain means the output voltage will be exactly equal in magnitude with the input voltage.  Voltage follower In the above figure a non-inverting…