Explain in brief forwards and reverse active regions of operation in BJT.

Explain in brief forwards and reverse active regions of operation in BJT.

Ans.  Mostly, in linear  applications, BJT is operated in forward active region. When VBE >0.5 V and VBC < 0.3 V, then the terminal variables simplify to

M

It is convenient to  use IC and IB rather than IC and IE as the dependent variables if modeling the BJT. F si give by

F =    M                                                                                          …….(iii)

From equations (i) and (ii), Ic and IB can be written as

IC = ISe (vbe/vt)                                                                                        …….(iv)

IB =  M e(vbe/vt)                                                                                                  …….(v)

BJT works as a good current amplifier in forward active region, from the base to the collector with the gain relationship

M

 

Base-to-emitter current gain in the reverse active region is given as follows –

M

 

Share this post