Description : Why is AC better for long distance power transmission than DC ?
Last Answer : ac is more economical to transmit for long distances . wires can be made smaller by step up transformer .. since major cost are wires to transmit .. then at the end of distance step down transformer is used for commercial use.
Description : Is the power line voltage available in our homes a dc or an ac voltage?
Last Answer : The power line voltage available in our homes is AC. Mobile dwellings are the most commonly DC-supplied homes and even then they tend to include AC supply for heavier loads.
Description : Draw symbol of LED and explain it’s working principle.
Last Answer : Construction of LED: The basic structure of LED is shown in fig.(a). The active region exists between the p and n regions. The light emerges from the active side in all the directions when electron hole-pairs ... fig.(c). In this way an LED emits light. This is the principle of operation of LED.
Description : What is photodiode? Draw the symbol and explain operation of photodiode.
Last Answer : A photodiode is a light detector that converts light into an electrical current. A photodiode is a semi-conductor device, with a p-n junction and an intrinsic layer between p and n layers ... current is independent of reverse bias voltage. Reverse current is mostly depends on the light intensity.
Description : AC power plugs and sockets
Last Answer : .embed-container { position: relative; padding-bottom: 56.25%; height: 0; overflow: hidden; max-width: 100%; } .embed-container iframe, .embed-container object, .embed-container embed { position: absolute; top: 0; left: 0; width: 100%; height: 100%; }
Description : AC power
Last Answer : Ac power is in sinusoidal wave form .Alternating current pulsating sinusoidally that is positive half cycle and negative half cycle.
Description : Explain power in single phase AC circuit.
Description : Draw symbol of NPN and PNP transistors.
Last Answer : symbol of NPN and PNP transistors
Description : Define resistor and draw symbol of variable resistor.
Last Answer : Resistor: A resistor is an electrical component that limits or regulates the flow of electrical current in an electronic circuit. Symbol of variable resistor:
Description : Draw symbol & V-I characteristics of (i) LASCR (ii) DIAC (iii) TRIAC
Last Answer : (i) LASCR: (ii) DIAC: (iii) TRIAC:
Description : Draw the symbol of LED & photodiode.
Last Answer : Symbol of LED & photodiode
Description : What is the symbol of a capacitor?
Last Answer : symbol of a capacitor
Description : What is the symbol of acceleration?
Description : In an A.C. circuit power is dissipated in?
Last Answer : In an A.C. circuit power is dissipated in resistance only.
Description : The apparent power drawn by an A.C. circuit is 10 kVA and active power is 8 kW. The reactive power in the circuit is?
Last Answer : The apparent power drawn by an A.C. circuit is 10 kVA and active power is 8 kW. The reactive power in the circuit is 6 kVAR.
Description : The input of an A.C. circuit having power factor of 0.8 lagging is 40 kVA The power drawn by the circuit is?
Last Answer : The input of an A.C. circuit having power factor of 0.8 lagging is 40 kVA The power drawn by the circuit is 32 kW.
Description : Pure inductive circuit takes power from the A.C. line when?
Last Answer : It takes power when voltage decreases and current increases.
Description : (b) Consider the circuit shown under the DC-steady-state condition. (i) Re-draw the circuit by replacing the capacitor and inductor with open and short-circuit. (ii) ... and the voltage, VC. (iii) Calculate the energy stored in the inductor and capacitor, respectively.
Description : What are some symbols associated with Persephone?
Last Answer : Persephone.
Description : Total instantaneous power supplied by a 3-phase ac supply to a balanced R-L load is
Last Answer : Total instantaneous power supplied by a 3-phase ac supply to a balanced R-L load is constant
Description : What is the advantage of AC over DC electrical transmission?
Description : Alternating current (AC)
Last Answer : AC stands for Alternating Current meaning voltage or current that changes polarity or direction respectively over time. An Alternating Current (AC) is an electric current whose magnitude ... energy are known as alternators and are simpler construction than DC electromechanical generators.
Description : Why are DC motors used in trains and not AC motors ?
Last Answer : The reason is torque. torque is inversely proportional to speed..i.e when th knowe train comes to rest position to motion.. initial speed is zero..so it requires high starting torque for ... current will flow through field and armature coils then maximum torque is available at the intial condition.
Description : Why is AC considered more efficient than DC?
Last Answer : Ac is more efficient than dc because it is easy to maintain and change the voltage of ac for transmission and distribution purpose. Plant cost of ac transmission is much lower compared to dc transmission. When fault occurs it is easy to interrupt ac supply.
Description : Which is more dangerous AC or DC and why ?
Last Answer : Dc is more dangerous than Ac because in Ac the voltage will varies but in dc the constant voltage
Description : Why can't we store AC in batteries instead of DC ?
Last Answer : Because the direction of the current changes in AC electricity, you cannot directly store the power. Placing a capacitor in an AC circuit has no effect on the alternating flow of the electricity. The only ... is indirectly, by storing DC and then using a power inverter to convert the DC to AC.
Description : What is the conversion between. AC to AC ? DC to DC? AC to DC? DC to AC ?
Last Answer : 1.ac to ac is regulation 2.dc to dc is chopper 3.ac to dc is rectifier 4.dc to ac is inverter
Description : AC generator
Last Answer : A.C power can be generated as a single phase or as a balanced poly-phase system. However, it was found that 3-phase power generation at 50 Hz will be economical and most suitable. Present day three phase generators ... has uniform air gap (figure 2.1(b)) and used when speed is high.
Description : Define : i) Average value ii) RMS value of an AC Wave.
Last Answer : i) Average value: The average value is defined as the average of all instantaneous values during one alternation . That is, the ratio of the sum of all considered instantaneous values to the ... as produced by the alternating current when flowing through the same resistance for the same time.
Description : AC Circuits with Resistance but No Reactance
Last Answer : AC Circuits with Resistance but No Reactance AC Circuits with Resistance but No Reactance Series resistances let two resistances R 1 and R 2 are connected in series as shows in figure and there ... voltage. Voltage V A is common to both the branch hence voltage V A is common reference.
Description : What is the need of polarity marking in polyphase AC circuits?
Last Answer : Need of Polarity Marking in Polyphase AC Circuits: i) Polarity marking of terminals provides reference polarity for better understanding of system, even if the polarity of ac voltage changes ... of current transformers in relay protection circuit and getting desired performance is very difficult.
Description : Explain how sinusoidal AC voltage is generated by using simple one loop generator.
Last Answer : An electric current produced by means of electrical machine is known as generator which converts mechanical energy into electrical energy. When conductor cuts the magnetic flux, emf induced in it. (Faraday' ... upon position of armature. The nature of emf is alternating as shown by the waveform.
Description : ‘PMMC instrument is not suitable to measure AC quantity’. State the reason.
Last Answer : The direction of force exerted on moving coil depends on the direction of current flowing through moving coil. If the direction of magnetic field is kept constant, it produces unidirectional torque if the current is ... on the coil in one cycle to zero. Hence the meter cannot read A.C. quantities.
Description : Write short notes on 3 phase AC system.
Description : Distinguish between AC and DC.
Last Answer : Particulars Direct Current Alternating Current Definition It is the current whose magnitude and direction do not change with respect to time. It is the current whose ... system, electroplating, Battery charging, Traction. AC machines, Domestic and industrial supply.
Description : The main advantage of AC over DC is: (A) Conversion flexibility from one voltage level to other (B) AC can be easily converted into DC by using a rectifier (C) AC is easy to maintain & can be easily distributed at long distances (D) All of the above
Last Answer : Ac is easy to maintain and ac can be easily converted to dc by rectifier .There is no commutator for conversion in ac that's why ac machines are weight less and more efficiency.ac machines occupy less space than dc .
Description : The ac bypassing of RF by CF in a common emitter configuration : (A) increases ac signal across emitter -base junction (B) decreases ac signal across emitter -base junction (C) decreases voltage amplification (D) stabilizes the Q -point
Last Answer : The ac bypassing of RF by CF in a common emitter configuration : increases ac signal across emitter -base junction
Description : Which of the following motors can run on both AC and DC? A) Universal motor B) Dual wattage motor C) Flexible motor D) All the above
Last Answer : Which of the following motors can run on both AC and DC? A) Universal motor B) Dual wattage motor C) Flexible motor D) All the above
Description : A parallel AC. circuit in resonance will?
Last Answer : A parallel AC. circuit in resonance will have a high impedance.
Description : In AC. circuits, laminated iron is invariably used in order to?
Last Answer : In AC. circuits, laminated iron is invariably used in order to reduce eddy current loss.
Description : In an AC. circuit, a low value of kVAR compared with kW indicates?
Last Answer : In an AC. circuit, a low value of kVAR compared with kW indicates high power factor.
Description : Do AC induction motors have back EMF?
Description : Do cell phones use AC or DC current?
Last Answer : DC of course.
Description : Why does a transformer only work with an AC supply?
Last Answer : The transformer work depends on the induction as main principle ,for that AC is the right means
Description : Is current from a battery AC or DC?
Last Answer : The current from the battery is DC
Description : How does AC current change direction?
Last Answer : This is because the angle at which the magnetic fields cuts across a winding changes its poles thus current has to change dirention .
Description : What is the direction of an AC current?
Last Answer : The magnitude and direction of alternating current is changes with respect to time. So for half cycle it is positive and for next half cycle it is negative.
Description : Why do we use AC current in our homes?
Last Answer : We used it for cooking rice, For washing clothes and for lights in the house.
Description : Can you apply Thevenin's theorem in an AC circuit?
Last Answer : It can be applied to AC circuits
Description : Can we apply the superposition theorem to AC circuit?