are the values of dc currents in a transistor different in ac analysis of the transistor...like is the value of Ib cannot be used in ac analysis..also how to get the value of beta if you are given min to max...thank you in advance..

 

are the values of dc currents in a transistor different in ac analysis of the transistor...like is the value of Ib cannot be used in ac analysis..also how to get the value of beta if you are given min to max...thank you in advance..

The bias conditions in an amplifier are often considered in a DC analysis, while AC methods and small-signal analysis may treat signal amplification. One way of representing conditions in circuits uses capital letters to denote quiescent or DC conditions (Ic, Ib), and lower-case variables (ic, ib) for incremental or AC variations. If that is what you are referring to, yes, you need to avoid mixing these things up.

It is harder to see what you mean in your question about how to "get the value of beta if you are given min to max". The whole point is that one cannot be sure of the value. For this reason, circuits should be designed to be tolerant to variations in beta. Feedback biasing circuits and negative feedback in amplifiers are among etechniques used to address this issue.