UPPSC AE Electrical key terms

A linear two-terminal network can be replaced by one voltage source in series with one resistance. The source equals the open-circuit voltage; the resistance equals the network resistance seen with sources killed.

Any linear two-terminal network can be modelled as one current source in parallel with one resistance. The current is the short-circuit current and the resistance is found like Thevenin resistance.

In a linear circuit with several independent sources, the response in any branch equals the algebraic sum of responses produced by each source acting alone, with all other independent sources set to zero.

The cosine of the phase angle between sinusoidal voltage and current in an AC circuit; it equals real power divided by apparent power and indicates how effectively current does useful work.

The power that oscillates between source and reactive elements such as inductors and capacitors without net energy transfer; measured in volt-amperes reactive (VAR), it equals VI sin φ in single-phase circuits.

The product of RMS voltage and RMS current in an AC circuit, measured in volt-amperes. It combines real and reactive power as the hypotenuse of the power triangle.

The condition in an AC circuit where inductive and capacitive reactances are equal in magnitude, so they cancel; impedance becomes purely resistive and current peaks at the resonant frequency.

A dimensionless measure of a resonant circuit's sharpness, defined as resonant frequency divided by bandwidth, or as reactance divided by resistance; higher Q means narrower bandwidth.

A static electromagnetic device with two or more coupled windings that transfers AC power between circuits, changing voltage and current levels while keeping frequency unchanged and ideally conserving apparent power.

Power dissipated as heat when alternating magnetic flux induces circulating currents inside a conducting core. It grows with the square of frequency and flux density and is reduced by laminating or using high-resistivity core material.

Energy lost per cycle as the core material is repeatedly magnetised and demagnetised, proportional to the area of the B-H loop and to frequency; reduced by choosing soft magnetic materials with narrow loops.

In an induction motor, the difference between synchronous speed and rotor speed, usually expressed as a fraction of synchronous speed; it is zero at no load and one at standstill.

The rotational speed of the rotating magnetic field in an AC machine, equal to 120 times frequency divided by the number of poles; the rotor of a synchronous machine runs exactly at this speed.

A curve showing how an induction motor's developed torque varies with slip. Torque rises steeply to a maximum at breakdown slip, then falls, and stable operation normally occurs on the low-slip portion.

The distortion and weakening of the main field in a DC or synchronous machine caused by the magnetic field set up by current flowing in the armature winding; it shifts the neutral axis and affects commutation and voltage regulation.

The process in a DC machine by which current in a coil is reversed as the coil passes the brush position, so that alternating internal currents become direct current at the terminals.

A method of expressing electrical quantities as fractions of chosen base values of voltage, current, power and impedance, simplifying calculations and comparison of machines of very different ratings.

The maximum short-circuit current a network can deliver at a point, determined mainly by source voltage and total impedance to that point; used to select switchgear rupturing capacity.

A switching device that makes, carries and interrupts fault current automatically, extinguishing the arc between contacts so that a circuit can be isolated safely without manual intervention.

Deliberate connection of exposed conductive parts or a neutral point to the general mass of earth, providing a low-impedance path for fault current and limiting touch and step voltages for safety.

The tendency of alternating current to concentrate near the surface of a conductor as frequency rises, which raises effective resistance and reduces the useful cross-section carrying current.

Non-uniform current distribution in a conductor caused by the magnetic field of nearby current-carrying conductors, increasing AC resistance, especially in closely spaced cables and windings.

Control schemes where one controller's output sets the reference for another, used in multi-loop drives and power plants to improve speed of response and disturbance rejection.

A feedback controller that sums proportional, integral and derivative actions on the error signal; the integral removes steady-state offset and the derivative adds damping to the response.

A four-layer semiconductor device that conducts in one direction only after a gate pulse, then latches on until current falls below the holding value; widely used in controlled rectifiers and motor drives.

An AC-to-DC converter using thyristors whose firing angle controls the average output voltage, allowing smooth regulation of DC motor speed and other loads.

Basic freedoms guaranteed to citizens by Part III of the Indian Constitution, enforceable through writs in the Supreme Court and High Courts; they include equality, speech, life, religion and constitutional remedies.

Guidelines in Part IV of the Indian Constitution directing the state towards social and economic welfare; they are not enforceable in courts but are fundamental in governance and law-making.

The power of the Supreme Court under Article 32 and High Courts under Article 226 to issue writs such as habeas corpus, mandamus, prohibition, quo warranto and certiorari to protect legal rights.

The three-tier rural local self-government system established by the 73rd Constitutional Amendment, with village, intermediate and district levels and reservations as laid down in Part IX.

A seasonal reversal of prevailing winds, most notably the Indian south-west monsoon that brings most annual rainfall from June to September, followed by a retreating north-east phase.

An intense low-pressure system over warm tropical oceans with organised thunderstorms and strong rotating winds; in the Indian region it is tracked by the India Meteorological Department and named under regional convention.

A period of rapid agricultural growth in India from the late 1960s based on high-yielding wheat and rice varieties, irrigation and fertiliser use, concentrated first in Punjab, Haryana and western Uttar Pradesh.

दो वर्णों या ध्वनियों के मेल से होने वाला परिवर्तन; जैसे विद्या + आलय से विद्यालय बनता है। हिन्दी व्याकरण में स्वर सन्धि, व्यंजन सन्धि और विसर्ग सन्धि प्रमुख भेद हैं।

दो या अधिक शब्दों के मेल से बने संक्षिप्त पद को समास कहते हैं; जैसे राजपुत्र अर्थात् राजा का पुत्र। तत्पुरुष, कर्मधारय, द्विगु, द्वन्द्व, बहुव्रीहि और अव्ययीभाव इसके भेद हैं।

वह अविकारी शब्दांश जो किसी शब्द के आगे जुड़कर उसके अर्थ में परिवर्तन या विशेषता लाता है; जैसे 'प्र' जोड़ने पर गति से प्रगति बनता है।

वह शब्दांश जो किसी शब्द के अंत में जुड़कर नया अर्थ या नई शब्द-श्रेणी बनाता है; जैसे 'लिख' में 'क' जोड़ने पर लेखक बनता है।

ऐसा वाक्यांश जिसका अर्थ शब्दों के सामान्य अर्थ से भिन्न, लाक्षणिक होता है; जैसे 'आँख का तारा' का अर्थ अत्यंत प्रिय व्यक्ति होता है।

जनसमाज में प्रचलित पूर्ण वाक्य के रूप में कही जाने वाली सूक्ति, जिससे कोई व्यावहारिक शिक्षा या अनुभव व्यक्त होता है; जैसे 'अंधों में काना राजा'।

Words that carry closely similar meanings in a given context, such as 'abundant' and 'plentiful'. Examiners test the ability to choose the word that fits register and collocation, not merely a dictionary equivalent.

Words with opposite meanings, such as 'scarce' and 'abundant'. Questions often require picking the exact opposite in sense rather than a loosely contrasting word.

A fixed expression whose meaning cannot be deduced from its individual words, such as 'to bury the hatchet' meaning to make peace; usage and preposition choice must be memorised.

A single word replacing a descriptive phrase, such as 'philanthropist' for a person who gives generously to good causes; a standard vocabulary item in objective English papers.

Two ways of presenting the same action: active voice makes the doer the subject, passive voice makes the receiver the subject and uses a form of 'be' with the past participle.

Two ways of reporting utterances: direct speech quotes the exact words in quotation marks, while indirect speech reports them with shifted tense, pronouns and time words, without quotation marks.