Re: bjt emitter current rating

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Gerald  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

It depends,  if it stays active the collector and emitter current are 
essentially the same so I would think the ratings would be the same.   Ie = 
(1+hfe)*Ib and Ic=hfe*Ib.  hfe (current gain) is often 100+ when the 
transister is active.

When saturated Vce< ~.3v and Vbe= ~.7v   The collector current will be 
limited by the collector emitter circuit and the base current will be 
determined by the base-emitter circuit (accounting for the fact that the 
emmitter current is the sum of the base and collector currents). Reasonable 
approximation to just short the base to collector to emitter and determine 
the currents (easy when no emitter resister).

But then again, you are talking about ratings - YES

Gerry R.


> Original poster: "Anthony" <ant17@xxxxxxxxxxxxxxxx>
>
> hi guys i was hoping someone might be able to tell me is the emitter 
> current rating of a npn transistor same as the collector rating if someone 
> could shed some light on this i would be greatful