Answer / yuvi

The colour of an LED is determined by the semiconductor
material used in it

Answer / ragu

THE FACTORS DEPEND UPON THE WAVE LENGTH OR FREQUENCY OF THE
LIGHT EMITTED. IT IS BASICALLY DEPENDS UPON THE CHARGE THAT
IS DISCHARGE DURING THE JUMPING OF ELECTRONS FROM HIGHER
ENERGY LEVEL TO LOWER ENERGY LEVEL..

Answer / kaparapu sreekanth

colour of LED depends on frequency,so colour of light varies by adding impurities while doping

If the battery is in charging condition means, battery is which type of load? Capacitive or Resistive load?

2 Answers   Crisp,

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What is breather? why we use it ?

3 Answers  

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1. A 380 / 220 V r.m.s. 3-phase 4-wire circuit carries loads of 8 + j8.1 ohm; 4 + j4.1 ohm; and 2 +j2.1 ohmin the three phases respectively. The length of the circuit is 100 m, and the resistivity of the phase conductors is 0.0005 Ω/m. The neutral conductor is of the same size as the phase conductors. a) Select a reference angle 0for the first phase. Then write down the three phase voltages in both polar format and complex number format. b) Make appropriate assumptions, and take temperature effects on resistance is insignificant. Calculate the currents in the three phases. (Note: Determine conductor resistance, and apply Kirchhoff’s Voltage Law) Based on the result, suggest a main switch rating for the circuit. c) Show your preferred direction of neutral current in a diagram, and then determine its value. (Note: Apply superposition principle, and Kirchhoff’s Current Law) Use its magnitude to show that in this circuit, the unbalanced load may increase the voltage drop in some of the phases. (Note: Also observe the common volt drip in neutral) State your assumptions, if there are any. d) Suddenly the neutral wire of the circuit is broken. Estimate the new currents in the first phase, i.e. Phase L1. State your assumptions, if there are any.

0 Answers  

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IT IS SAID THAT THE OLTC OPERATION SHOULD NOT BE PERFORMED WHEN THE TRANSFORMER IS GENERATION TRANSFOREMR/STEP UP MODE. WHY IS IT SO?

1 Answers   MSETCL Maharashtra State Electricity Transmission Co Ltd,

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I am an electrical power engineer and arranged power system for a data center, I installed MCB, ELCB and erthing system TN-C-S. But some times several ELCBs Disconnect circuits at the same time! what may be the reason? (the ELCBs are 25A ,30mA)

9 Answers  

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Will The Rated Capacity of 20 MVA ,220/6.6 KV, ONAN cooling Power Tranformer be increased up to 25 MVA with respect to its %Impedence by ONAF cooling with same rating..?

2 Answers   Ambuja,

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how motor should be connected i.e star-delta or star-star or delta-delta ?

3 Answers   GSE,

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To measure insulation resistance of 11KV cable between core & armour, what should be the test voltage & duration?

4 Answers  

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what is feeder bay?

0 Answers  

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For my plant the electricity department charging some amount for t/f losses. May i know what are transformer losses

1 Answers   L&T,

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What is meant by term Back to back in HVDC transmission?

1 Answers   SSC,

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Slow acting fuses are most often used for which application a) Lighting circuit b) heating circuit c) Motor D) Radar circuit

1 Answers  

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