XOR GATE USING NAND GATE

Hi guys.In any Electrical Interview(Engineering services Interview or GATE Interview) this question will be surely asked."Form XOR Gate using NAND Gate logic or NOR Gate logic (Universal Gates)."The answer for this question can be formed using the truth table of XOR Gate and truth table of NAND Gate.In Interviews they might ask you to form other logic gates using the Universal Gates(NAND Gate and NOR Gate). So be prepared to form other logic gates too.If you have any doubts please post your doubts in the comments section.

TRUTH TABLE FOR NAND GATE(UNIVERSAL GATE)

EXCLUSIVE OR GATE USING NAND GATE

 

TRUTH TABLE FOR EXCLUSIVE OR GATE

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