Dynamic current amplification:
Another way of specifying current amplification is as the ratio of difference in IC to difference in IB. Abbreviate words the difference in by letter d. Then, according to second definition:
Current amplification = dIC/dIB
A graph of collector current versus base current (IC vs IB) for a hypothetical tran- sistor is shown in the figure given below. This graph resembles. Three different points are shown, corresponding to various bias values.
Figure- Three different transistor bias points.
The ratio dIC /dIB is different for each points in graph. Geometrically, dIC /dIB at given point is the slope of a line tangent to curve at that particular point. The tangent line for point B in the figure given below is a dotted, straight line; the tangent lines for points A and C lie along the curve. The steeper the slope of line, greater is dIC /dIB.