Difference of current and voltage biasing

[malaganas]

Hi,

What is the difference of biasing a transistor with a dc current source at its gate instead of a dc voltage source?

Regards

 

[Surendhar M]

Go through the link

https://www.electronics-tutorials.ws/amplifier/transistor-biasing.html

 

[LvW]

Because I do not trust the above mentioned tutorial link (several errors) I recommend another (serious) document given here:

https://users.ece.gatech.edu/mleach/ece3050/notes/bjt/bjtbias.pdf

 

[malaganas]

Hi,

I´m sorry, I was not very clear before. I was more interested in differential pairs, I have seen different architectures where the gate of the biasing transistor is sometimes a dc voltage and sometimes a current source.

Can someone explain me the difference here?

Regards

 

[BigBoss]

Hi,

I´m sorry, I was not very clear before. I was more interested in differential pairs, I have seen different architectures where the gate of the biasing transistor is sometimes a dc voltage and sometimes a current source.

Can someone explain me the difference here?

Regards

If you use resistor, the tail current will be variable with temperature and bias condition of the pair transistors and also a voltage drop will occur across the resistor for nothing.If you use a current source, it will be independent from temp. and any extra voltage drop won't occur..

 

[malaganas]

If you use resistor, the tail current will be variable with temperature and bias condition of the pair transistors and also a voltage drop will occur across the resistor for nothing.If you use a current source, it will be independent from temp. and any extra voltage drop won't occur..

Hi,

Yes current source should be. Now you achieve this current source with a biasing transistor.

My question is what is the difference biasing this transistor with a dc current and a dc voltage.

Regards