Modelling current source with BJT

[Nerdie]

I have to design a current source, but in the process I should only use 1 bjt and the current source should be beta independent. How is it even possible?

 

[crutschow]

Hint: The collector of a BJT has a high impedance and an emitter resistor provides feedback to stabilize the gain.

 

[Nerdie]

Ah thanks for the hint but doing it with a series of zener diodes at base worked out in simulation as well. Hope it will work in practice.

 

[crutschow]

Ah thanks for the hint but doing it with a series of zener diodes at base worked out in simulation as well. Hope it will work in practice.

Try varying the beta of the transistor and see what happens. You will find that circuit will not meet the beta independent requirement that you need for your current source.