The Designer's Guide Community Forum

The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl
Design >> Analog Design >> abt saturation current in BJT
https://designers-guide.org/forum/YaBB.pl?num=1224482819

Message started by VINAY RAO on Oct 19^th, 2008, 11:06pm

Title: abt saturation current in BJT
Post by VINAY RAO on Oct 19^th, 2008, 11:06pm

In mos ,saturation region means the maximum current that cant be increased more i.e means current is saturated.But in BJT it is reverse.WHY in BJT even though current can be increased ,region we get when both the junction are forward biased is called saturation region??
I hope for positive reply..Pl help me to understand..

Title: Re: abt saturation current in BJT
Post by raja.cedt on Oct 20^th, 2008, 12:00am

hi,
in bjt saturation means not regarding current,instead it means toal charge in the base has reached saturation.i hope u got my point

Title: Re: abt saturation current in BJT
Post by VINAY RAO on Oct 20^th, 2008, 11:28pm

Sry,iam not clear abt it.But chrge in base will be increased in base in saturation region, will it nt increase further if we increase forward bias voltage of CB junction ( means when we r driving device more into saturation region)?????

Title: Re: abt saturation current in BJT
Post by raja.cedt on Oct 21^st, 2008, 1:33am

hi,
i mean when BJT is in active region ic=Β*ib,wheras when its in saturation region ic<Β*ib.hence even though u increase base drive ib will increse,but inside recombinations will keep ic to be at the same value.means net charge is fixed.where as in active regoin charge keeps increasing with base drive and hence collector current(note that here charge is increasing ) .i hope u got my point

Title: Re: abt saturation current in BJT
Post by raja.cedt on Oct 22^nd, 2008, 2:01am

hi, i forgot to mention about the book name "modular series on BJT".they have given very clearly this point.

Title: Re: abt saturation current in BJT
Post by VINAY RAO on Oct 23^rd, 2008, 10:40pm

Thanks a lot,,do u hv soft copy of that book??

Title: Re: abt saturation current in BJT
Post by raja.cedt on Oct 23^rd, 2008, 11:25pm

no man,that to its a costly book.so u better buy the follwoing books.it is indian addition

Semiconductor Device Fundamentals by R. F. Pierret
(Addison Wesley, 1996)
Thank you,