Current Electricity

Which of the following resistivity ( ) v/s temperature ( T ) curves is most suitable to be used in wire bound standard resistors?

1. [figure]
2. [figure]
3. [figure]
4. [figure]

Answer

(4) [figure]

Solution

A standard resistor must keep its resistance fixed, so must be almost independent of T (very small , as in manganin).

Curves (1), (2), (3) change strongly with T; curve (4) is nearly flat.

curve (4)

Answer: (4)