Difference between Bjts and Fet

There are many difference between Fet and Bjts

Bjts: bipolar junction transistor

A bjts ( bipolar junction transistor ) a types of transistor...........
its operation depend upon two types of semiconductors like P type and N type materials.........

   BJTs can be used as amplifies switches, or in oscillator. 
  BJTs can be found either as individual discrete components, or in large numbers as 
parts of integration circuits

1.  bipolar junction transistor is lager in size as compare to fet
2.  bjts have very low resistance approximately in ohms that why bjts burn when 
large voltage is applied
3.  bjt's devices have dependent currents for example collector current in transistor 
is depend upon base current and beta
4.  beta is not constant in every case but in bjts beta show very large variation with 
temperatur

Fet: field effecting transistor

The field-effect transistor is a transistor that uses an electric field to control  shape 
and hence the conductivity of the channel of one type of charge carrier in a 
semiconductor material....................

   FETs are unipolar transistors as they involve single-carrier-type operation. 
  The concept of the FET predates the bjts, though 
  it was not physically implemented until after BJTs due to the limitations 
of semiconductor meterial and the relative ease of manufacturing BJTs 
compared to FETs at the time.

1.  The size of fet is very small as compare to bjts
2.  fet have a large internal resistance about in maga ohms so it can bear large 
voltage without dammage
3.  fet have depended voltage instead of dependent current 
4.   value of beta also vary in fet but in fet variation of beta is very small it is 
negligible