Page 10 - Electrical Materials_Neat

Electrical Materials

Electrical conductivity is very useful property since values are affected by
such things. Therefore, electrical conductivity information can be used
for measuring purity of water, checking for proper heat treatment of
metals and inspecting for heat damage in some materials.

(iii) Dielectric Strength
It is property of material which indicates ability of material to withstand
at high voltages. Usually, it is specified for insulating material to
represent their operating voltage. Which material having high dielectric
strength can withstand at high voltages.

(iv) Temperature Coefficient of Resistance

Temperature coefficient of resistance of material indicates change in
resistance of material with change in temperature. Resistance of
conductor changes with change of temperature. As noted above, electrical
conductivity values are reported at 20 degree centigrade. This is done
because conductivity and resistivity of material is depending on
temperature. Thus conductivity of materials decreases as temperature
increases.

(v) Thermoelectricity

If link formed by joining to two metals is heated, a small voltage of
millivolt is produced. This effect is called thermoelectricity or
thermoelectric effect. This effect forms basis of operation of
thermocouples and some temperature based transducers. This can be used
to generate electricity, to measure temperature and to measure change is
temperature of objects.

3.2. Magnetic Properties of Material

Origin of magnetism lies in orbital and spin motions of electrons and how
electrons interact with one another. Magnetic properties of material are
those which determine ability of material for particular magnetic
application. Read Engineering Materials – Deformation of Solid
Materials.

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