interview question related to fundamental

Interview question related to active and passive component

Ques:-what is component?

Ans;-component are the basic part of electronic equipment.

Ques:-what is active component?

Ans:-active components always produce power or energy from their work. The energy or power generated by these components is in the form of voltage and current, these component can also amplify signals. These component have the capability to increase the power of signal by amplify it

Example:- transistors, integrated circuit.

Ques:-what is passive component?

Ans:-a passive component never requires power or energy to work unlike the active component. this mean that these component do not need any power storage. Hence their circuit do not produce energy neither they amplify signals.

Example:- resistors, capacitors, inductors etc.

Ques:-what is resistors?

Ans:-resistors:-resistor is an electronic component that resists the current by producing voltage between its two terminals.

Types of resistors:-

Fixed resistors:-the resistors that come with two wires are fixed resistors, these kind of resistors do not allow you to change the resistance.

Variable resistors:-these types of resistors allow you to change the resistance using a knob.

Some other types of resistors;-

*carbon film resistor

*carbon composition resistor

*metal oxide film resistor

*thermistor

Negative temperature coefficient thermistors

Positive temperature thermistors

Surface mount resistors.

Ques:-what is inductance?

Ans:-inductance is ability of device to oppose a change in the current flow .

The unit of inductance is Henry (H), symbol=  L

Ques:-what is inductor?

Ans:-inductor is device which has a specific value of inductance.

Types of inductor:-

*Surface mount

*Toroid type inductor

Ques:-what is use of inductor in computers?

Ans:- inductors are used in SMPS for storing energy.

Inductors are used to remove noise from motherboard.

Ques:-what is capacitance?

Ans:-capacitance is amount of energy stored at a given voltage drop by capacitor.

Ques:-what is capacitor?

Ans:- capacitor is a passive device that store electrical energy

It is consist of conductors separated by insulators , they are widely use in electronic component to block flow of direct current and allow alternating current to pass through the filter without interferences.

The unit of capacitor is Farad(F),   Symbol=C

Types of capacitor:-

*ceramic capacitor

Ques:-what is use of capacitors in computer?

Ans:-capacitors are used to store an electrical charge and used in timer circuit , it can be used with resistor  for generating timer.

To prevent unwanted triggering of other component such as relays capacitors are used to smooth the flow of current in  circuit.

Ques:-what is diode?

Ans:-diode is an electronic device, which allows current to flow only in one direction

Diode are formed by joining the N-TYPE and P-type semiconductor.

 The voltage applied to the semiconductor diode is referred as BIOS voltage. the BIOS voltage can be forward and reversed.

Ques:-write the type of diode?

Ans:-PN junction diode:-they are formed by combining a P-type and N-type semiconductor, the N-type semiconductors include negatively charged electrons and P-type semiconductors include positively charged holes, the junction is formed at the meeting point of semiconductors, due to motion of electrons and holes near the junction , a depletion layer is formed.

Zener diode:- A Zener diode allows current to flow from its anode to its cathode like a normal  semiconductor diode, but it also permits current to flow in the reverse direction when its "Zener voltage" is reached. Zener diodes have a highly doped p-n junction. Normal diodes will also break down with a reverse voltage but the voltage and sharpness of the knee are not as well defined as for a Zener diode. Also normal diodes are not designed to operate in the breakdown region, but Zener diodes can reliably operate in this region.

Zener diodes are widely used in electronic equipment of all kinds and are one of the basic building blocks of electronic circuits. They are used to generate low power stabilized supply rails from a higher voltage and to provide reference voltages for circuits, especially stabilized power supplies. They are also used to protect circuits from over-voltage, especially electrostatic discharge (ESD).

Light emitting diode:- A light-emitting diode (LED) is a two-lead semiconductor light source. It is a p–n junction diode, which emits light when activated.^[4]When a suitable voltage is applied to the leads, electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence, and the color of the light (corresponding to the energy of the photon) is determined by the energy band gap of the semiconductor. LEDs are typically small (less than 1 mm² ) and integrated optical components may be used to shape the radiation pattern

Ques:-what is avalanche breakdown?

Ans:- Avalanche breakdown is a phenomenon that can occur in both insulating and semiconducting materials. It is a form of electric current multiplication that can allow very large currents within materials which are otherwise good insulators. It is a type of electron avalanche. The avalanche process occurs when carriers in the transition region are accelerated by the electric field to energies sufficient to create mobile or free electron-hole pairs via collisions with bound electrons. It is occurs due to reverse current

Ques:-what is reverse current and how electron hole pair generated at junction?

Ans:-

when some p-type impurity in n-type material and n-type impurity in p-type impurity because of that some unwanted holes present in n-type semiconductor and some unwanted electrons present in p-type semiconductors due to some thermal heat .at reverse condition due to applied electric field  holes flow towards p-type n free electron moves towards n-type semiconductors ,the junction breakdown leading due to heavy flow of reverse current through the device. Due to this magnitude of reverse voltage increases so magnitude of kinetic energy of free electron is also increases. Then free electron hits to the another electron at high speed then new electron hole pair are generated and breakdown voltage occur. at result depletion layer vanished and finished.(when p-type terminal connected through low terminal of battery and vice versa)

Ques :- what is zener breakdown ?

Ans:- zener diode is highly doped p-n junction diode. Depletion layer will be very narrow 200 A*(armstrong) .when reverse BIOS is applied to the device due to this the electric field is increases because of small depletion width suddenly when we increases the reverse BIOS then reverse barrier of device breakdown known as zener breakdown .

Ques:-what is use of Diodes and Rectifiers in Computer?

Ans:-diode is used to convert AC into DC by neglecting the part of signal, rectifiers are specific assemblies of diode help convert AC to DC , they act as power regulations for your computer.

Rectifiers helps in reducing in power loss.

Ques:- what is transistor?

Ans:- a transistor is a three terminal device which amplifies an input signal.

Power consumption is low and efficiency is high.

Ques:-what is NPN transistor?

Ans:-NPN transistor-NPN is one of the two types of bipolar transistors, consisting of a layer of P-doped semiconductor (the "base") between two N-doped layers. A small current entering the base is amplified to produce a large collector and emitter current.

The main difference between the NPN and PNP transistor is, an NPN transistor turns on when the current flows through the base of the transistor. In this type of transistor, the current flows from the collector (C) to the emitter (E). A PNP transistor turns ON, when there is no current at the base of the transistor.

                                                            

Ques:-what is PNP transistor?’

Ans:-PNP transistor-The other type of BJT is the PNP, consisting of a layer of N-doped semiconductor between two layers of P-doped material. A small current leaving the base is amplified in the collector output. That is, a PNP transistor is "on" when its base is pulled low relative to the emitter.

pnp- Transistor Operation. The pnp transistor works essentially the same as the npn transistor. However, since the emitter, base, and collector in the pnp transistor are made of materials that are different from those used in the npn transistor, different current carriers flow in the pnp unit

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Ques:-what is BJT?

Ans:-a bipolar junction transistor is a three layer sandwich of doped semiconductor materials. The basic function of BJT is to amplify the electric current.

A bipolar junction transistor (bipolar transistor or BJT) is a type of transistor that uses both electron and hole charge carriers. In contrast, unipolar transistors, such as field-effect transistors, only use one kind of charge carrier. For their operation, BJTs use two junctions between two semiconductor types, n-type and p-type.

                               

Ques:-what is FET?

Ans:-FET(field effect transistor) has two layers of semiconductor material.

The field-effect transistor (FET) is a transistor that uses an electric field to control the electrical behaviour of the device. FETs are also known as unipolar transistors since they involve single-carrier-type operation. Many different implementations of field effect transistors exist. Field effect transistors generally display very high input impedance at low frequencies. The conductivity between the drain and source terminals is controlled by an electric field in the device, which is generated by the voltage difference between the body and the gate of the device.

                                                      

Ques:-what is MOSFET?

Ans:-MOSFET(metal oxide semiconductor field effect transistor) is made up of silicon semiconductor material between source drain terminals

The metal–oxide–semiconductor field-effect transistor (MOSFET, MOS-FET, or MOS FET) is a type of field-effect transistor (FET). It has an insulated gate, whose voltage determines the conductivity of the device. This ability to change conductivity with the amount of applied voltage can be used for amplifying or switching electronic signals. Although FET is sometimes used when referring to MOSFET devices, other types of field-effect transistors also exist.

Although the MOSFET is a four-terminal device with source (S), gate (G), drain (D), and body (B) terminals,^[1] the body (or substrate) of the MOSFET is often connected to the source terminal, making it a three-terminal device like other field-effect transistors

Ques:-what is difference between BJT and MOSFET?

Ans:-

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ques:- what is the use of transistor in computer?

Ans:-transistor is used in memory chips as a switch . with a number of transistors, a computer can store large amount of binary numbers represent  ordinary numbers and alphabets.