Confusion with biasing circuits (BJT)

Hello experts!

I was studying biasing circuits i.e. voltage divider bias, base bias, emitter bias, and both feedback biasing circuits i.e. collector feedback bias and emitter feedback bias.

Analysis of all these biasing circuits are so confusing. In voltage divider bias, base circuit analysis is done separately and collector circuit analysis is done separately.
When I use same method for other biasing circuits especially base bias(seems same as voltage divider bias) then result is wrong.

I don't know what are the final task should be. I mean in voltage divider bias we have to finally find base voltage. In base bias we have to find base current (probably). But in emitter we have to find collector current. What is this?

I don't know how to make it easily understandable to you. These all are the circuits making much confusion in my mind. Is there any key point to remember task that what should we find in each circuit?

Any help will be greatly appreciated.
Thank you.

Are you looking at common emitter amplifiers? There are plenty of threads here about it and other information on the internet. https://www.electronics-tutorials.ws/amplifier/amp_2.html

Keith

Hi Mustafa,
it`s not as complicated as it sounds.

The principle is as follows:
* The base-emitter diode of the BJT must be in "on" condition (forward biased) in order to allow a collector current.
* This can be achieved by (a) providing a suitable voltage in the range 0.6...0.7 volts between both nodes or (b) by sending a current through the B-E junction (normally in the µA- or lower mA range).
* Both alternatives can be realized without or (preferrably) with negative dc feedback at the same time (operating point stabilization against temperature and other unwanted influences)
* This feedback can be created by an emitter resistor or by a resistor between collector and base (instead connecting this resistor to the upper supply).
* Finally: These alternatives lead to the different bias schemes you were referring to.
________
A bit clearer now?

keith1200rs said:

Are you looking at common emitter amplifiers? There are plenty of threads here about it and other information on the internet. https://www.electronics-tutorials.ws/amplifier/amp_2.html

Keith

Click to expand...

Thanx for reply. But I am not looking for CE configuration. These are biasing methods.

---------- Post added at 19:15 ---------- Previous post was at 19:14 ----------

LvW said:

Hi Mustafa,
it`s not as complicated as it sounds.

The principle is as follows:
* The base-emitter diode of the BJT must be in "on" condition (forward biased) in order to allow a collector current.
* This can be achieved by (a) providing a suitable voltage in the range 0.6...0.7 volts between both nodes or (b) by sending a current through the B-E junction (normally in the µA- or lower mA range).
* Both alternatives can be realized without or (preferrably) with negative dc feedback at the same time (operating point stabilization against temperature and other unwanted influences)
* This feedback can be created by an emitter resistor or by a resistor between collector and base (instead connecting this resistor to the upper supply).
* Finally: These alternatives lead to the different bias schemes you were referring to.
________
A bit clearer now?

Click to expand...

Thanks for reply.
Actually my thread is about derivations for biasing methods. i.e. find the general formulas in order to handle these circuits. I think it should help you to understand my thread.

See these all informal terminology you speak or read are conventions to understand the architecture of biasing. They are not a defined terms. So for your confusion about how to tell/speak biasing (as voltage or current) at that node, depends upon what is the physical quantity , required to operate the device. So node (whether base or emitter) may be called current biased or voltage biased. BJT device , base may be voltage or current biased, but in MOSFET device, it is voltage biased only. you can't bias the MOSFET gate from current.
Now you need to read the operation of BJT and MOSFET, with various operating modes, and how to bias them? I guess you can bias cllector by constant current source or giving some voltage >VCEsat.