Deepu creation

  Important questions for interview: 1 . Explain about your self? 2. What is your goal? 3. What is your project? 4. Which role are you work? 5. How much cost are you 

 RECTIFIER  The rectifier is a circuit which offers low resistance to the current in one direction and high resistance in the opposite direction  It is sinusoidal signal to unidirectional flow and not pure DC In the input to the rectifier is a pure sinusoidal wave, the average value 9s such a wave is zero, since the positive half cycle and negative half cycle are exactly equal. Types of rectifier  1.half wave rectifier  2. full wave rectifier  Half wave rectifier  It is signal is given to the rectifier circuit, half wave rectifier circuit,the output will be as shown The average value of this wave form is not zero since there is no negative half hence a rectifier circuit converts AC to  unidirectional wave form with non zero a average value The rectifier device are semiconductor diodes foe low voltage signal and vacuum diodes for high voltage circuit. AC voltage is normally the AC main supply since the voltage 230v ,and such a high voltage cannot t...

  Important questions for interview in c ,Java python: C Important topics: 1.who is author? 2.c features  3.difference between local ,global, static variables? 4.pointers 4.functions 5.arrays 6.calloc and mallow 7.bit wise operators 8.differenence between array and pointers? 9. Structure  Java important topics: 1.oops concept 2.object and classes 3.method overriding  4.method overloading 5.collection frame work 6.multi threading 7.difference between C and C++ and Java? 8.which one is speed? 9. Packages in java Python important topices: 1.list,tuple,dictionaries 2.oops concepts 3.keywords in python 4 .data types 5. Slicing 6.python libraries 7. Decators 8.Features in python 9.packages

  LED The LED is an optical diode, which emitter light when forward biased. The symbol of LED which is similar to P-N junction diode apart from the two arrows indicating that the device emits the light energy.                                Symbol of LED  Operation of LED When p-n junction is forward biases the electrons cross the p-n junction from the ntype semiconductor Material and recombination with the holes in the p type semiconductor Material. The free electrons are in the conduction band. While the holes are present in the valance band. Thus the free electrons are at higher energy level with respect to the holes. When free electrons recombination with hole, it falls from conduction band to a valance band. The energy corresponding to the difference between higher level and lower released by an electron while traveling from the conduction band to the valance band. In normal diodes,this energy...

  Zener diode  The zener diode is a silicon p-n junction semiconductor device, which is generally operated in it reverse break down region. The zener diode are fabricated with precise breakdown voltage by controlling the doping level during manufacturing.                         Symbol of zener diode  Characteristics of zener diode The forward biased condition,the normal rectifier diode and the zener diode operate in similar. But the zener diode is designed to be operated in the reverse biased condition.  In reverse bias  condition,the diode carries reverse saturation current till the reverse voltage applied is less than the reverse breakdown voltage.when the reverse voltage excess reverse breakdown voltage, the current through it change drastically but the voltage across it remains almost constant. Such breakdown region is a normal operating region for zener diode. The breakdown characteristics fo...

  P-n junction diode An unbiased PN junction is a built in potential will be potential  will be developed at the junction. When PN junction is formed,the resulting two terminal device is called as junction diode. The P terminal is called as anode and N terminal is called cathode. Under unbiased condition,there is no conduction,that is no current exists in the device.for the current to flow the device must be biased suitably by baiasing it means the application of an external voltage.there are two methods of biasing a junction diode. 1. forward bias 2.reverse bias Forward bias The forward bias junction diode is as shown in below.by forward bias,it means that the positive terminal of external sources is connected to the P terminal and the negative terminal to the N material, respectively. By doing  so, the externally connected DC voltage established an electric field opposite to the potential barrier,there by reducing the potential barrier.the potential barrier is typically...

  Semiconductor  Material whose conductivity lies between that of conductor and insulator is called semiconductor Germanium and silicon have resistivity of the order of 100 ohms.  Some important semiconductor are silicon,Germanium, gallium,arsenide. Classification of semiconductor  Semiconductor are classified into two types 1.intrinsic semiconductor  2.extrinsic semiconductor  Intrinsic semiconductor or pure semiconductor  Germanium and silicon combine to form one crystal. Covalent bonds are formed by the sharing of the valence electrons by the neighboring atoms.at absolute zero temperature 0k ,as no energy is imparted,all the electron in the outer orbits remain in the valence bands.conseqzently,the semiconductor behaves as an insulator          Figure1 : Ge cystal at room temperature  However, at room temperature, some pf the electrons in the outer orbits may acquire sufficient to break the Covalent bonds in ge is 072ev ...

  CAPACITOR Capacitor is also called a condenser and is a linear passive circuit element, which has the capacity to store energy in the form of an electrical charge and produce a potential difference across its terminals. Symbol A capacitor basically consists of two parallel metal plates that are electrically separated by a distance d in meters with dielectric material between the plates.the most common types of dielectric material used are air,polyster, paper,poly propylene, mylar,ceramic,glass,oil                             C= €A/d Faraday Where k=€0€r €0= permittivity of free space=8.854×10-12F/M K= relative permittivity of the dielectric material between the plates Example problems  In the parallel plate condenser,the plates are separated by a distance of 0.1 cm and the area of the plates of the is 100 cm2 .express C in pf, if the dielectric medium is air. Answer: €=€0€r=8.854×10-12×0.91m2/0.001m  ...

  RESISTOR  Resistor is determine the flow of current in an electric circuit.the higher the resistance in the circuit,the smaller is the current in it and vice versa.  resistance is measured in ohms. All modern fixed value Resistor can be classified into four broad groups: Symbol  1.carbon composition resistor: carbon composition Resistor is manufactured from a mixture of finely ground carbon dust graphite and a non conducting ceramic  power to bind it all together. These are usually low wattage Resistor.  2.Firm Resistor firm Resistor consists of metal film,carbon film and metal oxide film Resistor types.these Resistor are made by depositing pure metals,such as nickel,or an oxide film,such as tin oxide,onto an insulating ceramic rod,or substrate made from conductive metal oxide paste.these are also low wattage Resistor  2.thick film Resistor are made by depositing a much thicker conductive paste of ceramic and metal called Carmen,onto an alumina ceram...

 Silicon controlled rectifier (SCR) It is also called as thyristors.it is used to high power applications.  Operation of SCR A silicon controlled rectifier is a four layer soid state current controlling device.the SCR are mainly used in electronic device.that required control of high voltage and power. On SCR conducts when a gate pulse is applied to it. It just like a diode. It has four layers  of semiconductor that forms to structure namely NPNP and PNPN and.it has three junction J1,J2, andJ3.  It has three terminals anode,cathode,and gate terminal SYMBOL OF SCR The anode connect to the P type material and cathode are connected to the N type material. And P is connected to bottom side of P material.  These are having two modes of operations are there: Forward blocking mode(off state): In this type of operation the anode of SCR is connected to the positive terminal of battery and cathode is connected to the negative terminal of the battery. And gate terminal is ...