CONDUCTOR

It is a type of material which easily allows to pass current.

Its resistance is range of milli ohm.

It has positive(+ve) temperature co-efficient means when temperature is increased, then resistance of wire is increased.

INSULATOR

It is a type of material which can't allow to pass current.

Its Resistance is range of mega ohm.

It has negative(-ve) temperature co-efficient, negative temperature co-efficient means, when temperature of surrounding is increased, the resistance of wire is decreased.

SEMICONDUCTOR

It is a type of special material which allows to pass current at some given temperature.

Its resistance is range of ohm

It has negative(-ve) temperature co-efficient, negative temperature co-efficient means temperature is decreased, then the resistance of semiconductor is increased.