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Showing posts from December, 2014

Resistance in Series and parallel

Resistance is only component availbale which converts current into voltage and voltage into current. Resistance in Series:- In Series resistance are additive and are as described below:- If there are resistances are R1, R2, R3, R4 ----- RN are connected in Series then equivalent resistance is given as  R (Eq.)= R1 + R2+ R3+ R4+ ---------------------+RN Series resistance is known as voltage divider circuit in which voltage get divided but current remains the same. Whenever resistance is added in series then equivalent resistance is getting increased. To know about capacitors in Series and Parallel Visit:- http://electrialstandards.blogspot.in/2015/05/capacitor-in-series-and-parallel.html Resistance in Parallel:- If there are resistances are connected in Parallel then equivalent resistance is given as :- If there are resistances are R1, R2, R3, R4 ----- RN are connected in Series then equivalent resistance is given as  ...

Light Emitting diode working principle; LED working principle

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Lighting emitting diodes mostly known as LEDs are now becoming integrated part of every Industry, Household , Shops and everywhere as they offer plenty of advantages some of them main are such as power saving and long life. There is curiosity arises how these LED’s will work? Working principle of the same is as below:- LED is capable of emitting a fairly narrow bandwidth of visible or invisible lights and LED emits lights usually of orange, red, yellow, or green colors. The invisible light that LED emits includes the infrared light. LED consists of a P-N junction diode. When electric current is applied to that P-N junction then that junction emits light .This sensation is generally called Electro-luminance in electronics. Electro-Luminance is defined as the emission of light from a semi-conductor under the influence of an electric field. At PN junction there are electrons at N- Region and Holes in P- region. These combine at PN Junction. Free electrons a...

Electrical Power in Series and Parallel circuits; Bulbs in series and Parallel

There is quite confusing question most of the time asked in interview is that if there are three bulbs having ratings as 60W, 30W and 20W and these bulbs are connected in parallel then which of these bulb will be brightest?? Answer to that question is that in Parallel   1               =  1  + 1  +   1 R(eq)             R1   R2    R3 Multiply both sides by Rated voltage square i.e. (V Rated ) 2 We get (V Rated ) 2    = (V Rated ) 2 + (V Rated ) 2   + (V Rated ) 2 R(eq)              R1                R2               R3 This means P(eq)= (P1)+...

Comparison between LED Vs Incandescent VS CFL lights

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LED vs CFL vs Incandescent Lights: Which is Better for You? When it comes to choosing lighting solutions for homes or offices, the three most common options are: Incandescent bulbs (traditional yellow bulbs), Compact Fluorescent Lamps (CFLs) , and Light Emitting Diodes (LEDs) . Each has its own advantages and disadvantages, but LEDs have emerged as the most energy-efficient and sustainable choice. Let’s break down the comparison. 1. Lifespan Comparison Incandescent Bulbs: ~1,200 hours CFLs: ~8,000 hours LEDs: ~50,000 hours 👉 Clearly, LEDs last up to 40 times longer than incandescent bulbs and more than 6 times longer than CFLs , which means fewer replacements and reduced waste. 2. Energy Efficiency (Power Consumption vs Lumens Output) LEDs produce the same amount of light (lumens) with much lower wattage. Lumens (Brightness) LED (Watts) Incandescent (Watts) CFL (Watts) 450 (≈ ...

Three phase Generator connected to load

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Generator connected to Isolated load:- When the prime mover I/p is increased while the excitation remains constant; it results in an increase in frequency. The increase in frequency increases the terminal voltage for the same excitation. The increase in  terminal voltage causes the static load to increase their respective demands as their power consumption is proportional to square of the voltage. The rotating load have their respective speed increases because of the increase in frequency that increases their synchronous speed. The increase in voltage results to increase in their developed torque and consequently the power demand may increase particularly when they are driving constant torque load. The twin factors results in as increased power demand by the rotating power load as well. The final conclusion is that an increase in prime mover I/P alone results in increase in frequency as well as increase in Unit loading. If the excitation increases w...