Mobility

 

The conductivity arises form mobile charge carriers of the semiconductor. 

Types of matter	Mobile charge carriers
Metal	Electrons
Ionized gas	Electrons & positive charged ions
Electrolyte	Position ions and negative ions

 

Mobility

• It is defined as the magnitude of the drift velocity per unit electric field.

       µ = V_d / E ………. ( 1 )

• Where µ = Mobility
• V_d = Drift velocity ( meter / second )
• E = Electric field  ( volt / meter )

The unit of mobility is = ( meter / second ) / ( volt / meter )

                                       = meter² / volt – second

The mobility is positive. The drift velocity is also given by

V_d = eτE / m……………… ( 2 )

Where τ = Average collision time of electrons

            e = Charge

             m = mass of electrons

from equation ( 1 ) and ( 2 )

µ = eτE / mE

µ = eτ / m

You may also like :

Function of shunt reactor

Types of smoothing reactor

Compare capacitor bank and single capacitor

Current harmonics and voltage harmonics