Ans: A resistor is a component which is used in electrical and electronic circuits for presenting resistance.
2Q: What is a carbon resistor?
Ans: A resistor made of carbon or graphite is called a carbon resistor.
3Q: How many types of carbon resistors are there?
Ans: Carbon resistors are of two types - (1) Composition type and (2) Film type.
4Q: What is a composition type resistor?
Ans: This type of resistors are made by compressing carbon powder which is mixed with a suitable resin binder.
5Q: What is a film type resistor?
Ans: A film type resistor is made by depositing hydrocarbon vapours on a fine ceramic pipe.
6Q: What are the merits of a carbon resistor as compared to a wire wound resistor?
Ans: (1) They have a small size and are light in weight.
(2) They are most suitable for high frequency circuits.
(3) They have low temperature coefficient value.
(4) High value resistors can be made easily.
7Q: What are the demerits of a carbon resistor as compared to a wire wound resistor?
Ans: (1) Their value changes by change in temperature and humidity etc.
(2) Their current carrying capacity and hence wattage is limited up-to 2watts.
(3) It is difficult to make a carbon resistor of a value below 2 ohms.
(4) Their stability and reliability are poor.
8Q: What are the values of various colours used in the colour code for carbon resistors?
Ans: The colours are valued in the following manner:
Black = 0; Brown = 1; Red = 2; Orange = 3; Yellow = 4; Green = 5; Blue = 6; Violet = 7;
Grey =8; White = 9.
9Q: What is the band type colour coding method?
Ans: In this method, the value of a resistor is expressed by 4 colour bands. The first band indicates first digit, second band indicates second digit and third band indicates the 'multiplier'. The fourth band indicates the tolerance of the resistor's value.
10Q: What is meant by tolerance in reference to resistors?
Ans: The percentage of change in the value of a resistor due to manufacturing defect or variation in humidity and temperature is called tolerance.
11Q: What are the various tolerance values of resistors and how are they expressed?
Ans: The tolerance of a resistor is expressed by a coloured ring or dot in accordance to the following - Brown = 1%; Red = 2%; Orange = 3%; Yellow = 4%; Golden = 5%; Silver = 10%; No colour = 20%.
12Q: What are the values of various colours used to indicate multiplier's value in carbon resistors?
Ans: The colours are valued for 'multiplier' in the following manner - Black =1; Brown = 10; Red =100; Orange = 10^3; Yellow =10^4; Blue = 10^6; Golden = 0.1; Silver = 0.01.
13Q: What is the body type colour coding method?
Ans: In this method, the colour of the body indicates first digit, the colour of the end indicates second digit and the colour of dot indicates the multiplier of the resistor's value. The tolerance is indicated by another dot marked on the other end of the body.
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