How does diode work in transistor circuit?

Thread Starter


Joined Jan 27, 2015
What is the role of diode that connect between the base and the emitter of the transistor?
(anode to the base and cathode to the emitter)
I know diode permits current flow in only one direction. Are there more?


Joined Mar 14, 2008
If you are talking about the intrinsic characteristics of the base-emitter junction, the "diode" is an inherent result of the base-emitter junction that forms part of the BJT structure. It is an artifact of the transistor design that looks like a diode when measured by itself but has no intentional "role" as a diode during normal transistor operation.


Joined Oct 2, 2009
Are you referring to the P-N junction that is inherent at the base-emitter junction of an NPN BJT (bipolar junction transistor)?

On its own it looks and behaves like a diode. In a transistor it plays a much more active role in that it controls the electron-hole flow within the transistor itself causing an increase of the collector-emitter current.