ONLINE ELECTRICAL ENGINEERING will contain ELECTRICAL ENGINEERING QUESTIONS & ANSWERS,ELECTRICAL INTERVIEW QUESTION & ANSWERS and important topics from ELECTRICAL MACHINES, POWER SYSTEMS ,POWER ELECTRONICS AND DRIVES and other ELECTRICAL ENGINEERING SUBJECTS.Objective tests will be conducted periodically which would be useful for exams like POWERGRID , NTPC ,NHPC ,ENGINEERING SERVICES ,IES ,ETC..FEEL FREE TO ASK YOUR DOUBTS REGARDING ELECTRICAL SUBJECTS.
Sunday, April 1, 2012
RESISTANCE COLOUR CODE FOR RESISTORS
In many interviews for the Electrical Engineers,they will give you a resistor in your hand ask you to tell the resistance value by seeing the colour codes on the resistor.In basic Electrical workshop, the first thing you learnt would be "How to identify the resistance value using colour code for the resistor ?".The way to remember the colour code is BB ROY of Great Britain has Very Good Wife.
Usually the resistors would be having 4-band code.Starting from the left the first 2 bands are the significant figure of the resistance value.The Third band is the decimal multiplier.There will be a much bigger gap between the third and fourth band.The fourth band indicates the tolerance value.Usually the colour code for tolerance is either Gold or Silver.
Gold indicates 5% tolerance level,Silver indicates 10% tolerance level and no fourth band indicates 20% tolerance level.Some resistors have five band colour.In that case first three bands are significant figures of the resistance value,fourth band is the decimal multiplier,fifth band is the tolerance level.
B - Black
B(ROY) - Brown R - Red O - Orange Y - Yellow G(reat) - Green Britain - Blue Very - Violet Good - Grey Wife - White