How does using a constant current source improve circuit performance in terms of biasing?

Question by ZleD: How does using a constant current source improve circuit performance in terms of biasing?

Best answer:

Answer by veeyesvee
Is this with respect to a BJT? And where is the current source? Be specific in your questions if possible.
A current source in emitter improves biasing, as the aim is to get a specified collector current, and collector current is almost 0.99* emitter current when current gain is 100. So it is a good method of biasing. When temperature changes, changes in collector current will not be significant. If the transistor is changed with one having twice the current gain, no problem as collector current will be 0.995* emitter current.
God forbid if you use a current source in base. When current gain doubles, collector current also doubles. So resulting operating point gets affected badly. The transistor may even go into saturation if collector has a fixed resistance.

What do you think? Answer below!

Leave a Reply

Your email address will not be published. Required fields are marked *

Categories