Electrical Engineering viva Questions and Answers:
Following are the Basic and Advanced Electrical Engineering viva Questions and Answers
Acceptor atoms – Trivalent atoms that accept free electrons from pentavhalent atoms.
Alpha – Ratio of collector current to emitter current in a Bipolar Junction Transistor (BJT). Greek letter alpha a is the symbol used.
Amplifier – A circuit that increases the voltage, current or power of a signal.
Analog – Information represented as continuously varying voltage or current rather than in discrete levels as opposed to digital data varying between two discrete levels.
Apparent power – Power attained in an AC circuit as a product of effective voltage and current which reach their peak at different times.
Barrier potential – The natural difference of potential that exists across a forward biased p-n
Baud rate – A unit of signalling speed equal to the number of signal events per second. Not necessarily the same as bits per second.
Beta – The ratio of collector current to base current in a Bipolar Junction Transistor (R.IT).
Cathode Ray Tube (CRT) – Vacuum tube used to display data in a visual Picture tube of a television or computer terminal.
Clamper – A diode circuit used to change the DC level of a waveform without distorting the waveform.
Clipper – A diode circuit used to eliminate part of a waveform
Common-Mode Rejection Ratio (CMRR) – The ratio of op-amp differential gain to common-mode gain. A measure of an op-amp’s ability to reject common-mode signals such as noise.
Covalent bond – The way some atoms complete their valence shells by sharing valence electrons with neighbouring atoms.
Diac – A two terminal bidirectional thyristor. Has a symmetrical switching mode.
Differentiator – A circuit in which the output voltage is in proportion to the rate of change of the input voltage. A high pass RC
Diffusion – Tendency of conduction band electrons to wander across a p-n junction to combine with valence band holes.
Diode – A two terminal device that conducts in only one direction.
Donor atoms – Pentavalent atoms that give up electrons to the conduction band in an n – type semiconductor material.
Doping – The process of adding impurity atoms to intrinsic (pure) silicon or germanium to improve the conductivity of the semiconductor material.
Drift – A problem that can develop in tuned amplifiers when the frequency of the tuned circuit changes due to temperature or component aging.
Efficiency – The amount of power delivered to the load of an amplifier as a percentage of the power required from the power supply.
Electromechanical transducer – Device that transforms electrical energy into mechanical energy (electric motor) or mechanical energy into electrical energy (generator).
Emitter – The semiconductor region from which charge carriers are injected into the base of a bipolar junction transistor.
Field Effect Transistor (FET) – A voltage controlled transistor in which the source to drain conduction is controlled by gate to source voltage.
Filter – Network consisting of capacitors, resistors and/or inductors used to pass certain frequencies and block others.
Flip flop – A bistable multivibrator. A circuit which has two output states and is switched from one to the other by means of an external signal (trigger).
Forward bias – A p-n junction bias which allows current to flow through the Forward bias decreases the resistance of the depletion layer.
Frequency-Division Multiplex (FDM) – Transmission of two or more signals over a common path by using a different frequency band for each signal.
Full Scale Deflection (FSD) – Deflection of a meter’s pointer to the farthest position on the scale.
Full wave rectifier – Rectifier that makes use of the full AC wave in both the positive and negative half cycles.
H-parameters (hybrid parameters) – Transistor specifications that describe the component operating limits under specific circumstances.
Half wave rectifier – A diode rectifier that converts AC to pulsating DC by eliminating either the negative or the positive alternation of each input AC cycle.
Integrator – A device that approximates and whose output is proportional to an integral of the input signal. A low pass filter.
Inverting amplifier – An amplifier that has a 180° phase shift from input to
Inverting input – In an operational amplifier (op-amp) the input that is marked with a minus sign. A signal applied at the inverting input will be given 180° phase shift between input and output.
Modulation – Process by which an information signal (audio for example) is used to modify some characteristic of a higher frequency wave known as a carrier (radio for example).
n-type semiconductor – A semiconductor compound formed by doping an intrinsic semiconductor with a pentavalent element. An n-type material contains an excess of conduction band electrons.
Noise – Unwanted electromagnetic radiation within an electrical or mechanical
Non-inverting input – The terminal of an operational amplifier that is identified by a plus sign.
n-p-n transistor – A bipolar junction transistor in which ap-type base element is sandwiched between an n-type emitter and an n-type collector.
Operational amplifier – A high gain DC amplifier that has a high input impedance and a low output impedance. Op-amps are the most basic type of linear integrated circuits.
Peak Inverse Voltage (PIV) – The maximum rated value of AC voltage acting in the direction opposite to that in which a device is designed to pass current.
Phase shift oscillator – An oscillator that sees three RC networks in its feedback path to produce the 180° phase shift required for oscillation.
Photodiode – A semiconductor diode that changes its electrical characteristics in response to illumination.
Pinch-off region – A region on the characteristic curve of a FET in which the gate bias causes the depletion region to extend completely across the channel.
Positive feedback – A feedback signal that is in phase with an amplifier input signal. Positive feedback is necessary for oscillation to occur.
Propagation delay – Time required for a signal to pass through a device or circuit.
Propagation time – Time required for a wave to travel between two points.
Pulse repetition frequency – The number of times per second that a pulse is transmitted.
Pulse repetition time – Time interval between the start of two consecutive
R-2R ladder – Network or circuit composed of a sequence of L networks connected in tandem. Circuit used in digital to analog converters.
Pulse rise time – Time required for a pulse to increase from 10% of its peak value to 90% of its peak value.
Pulse width – Time interval between the leading edge and trailing edge of a pulse at a point where the amplitude is 50% of the peak value.
Radar – Acronym for Radio Detection And Ranging a system that measures the distance and direction of objects generally in space.
Schottky diode – High speed diode that has very little junction capacitance. Also known as a hot-carrier diode or a surface-barrier diode.
Semiconductor – An element which is neither a good conductor or a good insulator, but rather lies somewhere between the two.
Single Sideband (SSB) – AM radio communication technique in which the transmitter suppresses one sideband and therefore transmits only a single sideband.
Solar cell – Photovoltaic cell that converts light into electric energy. Especially useful as a power source for space vehicles.
Superconductor – Metal such as lead or niobium that, when cooled to within a few degrees of absolute zero, can conduct current with no resistance.
Super heterodyne receiver – Radio receiver that converts all radio frequencies to a fixed intermediate frequency to maximise gain and bandwidth before demodulation.
Threshold voltage – For an enhancement MOSFET, the minimum gate source voltage required for conduction of source drain current.
Time Division Multiplexing (TDM) – Transmission of two or more signals on the same path, but at different times.
Transformer – Inductor with two or more windings –Through mutual inductance, current in one winding called a primary will induce current into the other windings called secondaries,
Transistor – Term derived from transfer resistor. Semiconductor device that can be used as an amplifier or as an electronic switch.
Triac – Bidirectional gate controlled thyristor similar to an SCR, but capable of conducting in both directions. Provides full wave control of AC power.
Wideband amplifier – Also called broadband amplifier. Amplifier with a flat response over a wide range of frequencies.
Zener diode – Semiconductor diode In which reverse breakdown voltage current causes the diode to develop a constant voltage. Used as a clamp for voltage regulation.