- It is defined as the ratio of the output current ( collector current ) and input current ( emitter current ).
- It is ratio of the change in collector current to the change in
emitter current at constant collector – base voltage ( V
_{CB}).

α = ∆I

_{C}/ ∆I_{E}……….. ( 1 )- It is defined as the ratio of the output current ( collector current ) and input current ( base current ).
- It is ratio of the change in collector current to the change in base current.

β = ∆I

_{C}/ ∆I_{B}………….( 2 )

*Relation between α and β*
As I

_{E}= I_{C}+ I_{B}
∆I

_{E}= ∆I_{C}+ ∆I_{B}
Therefore ∆I

_{B}= ∆I_{E}– ∆I_{C}………. ( 3 )
From equation ( 2 ) and ( 3 )

β = ∆I

_{C}/ ∆I_{E}– ∆I_{C}_{}
Divide numerator and
denominator by ∆I

_{E}_{}
β = [ ∆I

_{C}/ ∆I_{E}] / [ ∆I_{E}– ∆I_{C}] / ∆I_{E}_{}
= α / ( 1 – α )

β = α / ( 1 – α ) |

OR

β ( 1 – α ) = α

β – βα = α

β = α + βα

β = ( 1 + β ) α

α = β / ( 1
+ β ) |

You may also like :

## No comments:

## Post a comment