Question

Draw the circuit for studying the input and output characteristics of and transistor in CE configuration. Show, how, from the output characteristics, the information about the current amplification factor (β_ac) can obtained.

Answer 1

Current amplification factor (β_ac) is the ratio of change in collector current (ΔI_C) to the change is base current (Δ I_B) at constant collector voltage. i.e.

`beta_(ac) =(DeltaI_c)/(DeltaI_B) | v_(CE)` constant

Output characteristics represent the variation of I_C with V_C, keeping I_B constant.

From above graph at V_C = V, the value of collector current increase with the increase the base current I_B.

Thus,

`beta_(ac) = (DeltaI_c)/(DeltaI_B) |v_(CE)` constant    AC Current gain