Draw a typical output characteristics of an n-p-n transistor in CE configuration. Show how these characteristics can be used to determine output resistance.

Output characteristics is the plot between collector-emitter voltage (VCE) and the collector current (IC) at different constant values of base current (IB). Output resistance is defined as the ratio of the change in collector-emitter voltage (ΔVCE) to the change in collector current (ΔIC) at a constant base current IB. Initially, with the increase in VCE, the collector current increases almost linearly; this is because the junction is not reverse biased. When the supply is more than required to reverse bias the base-collector junction, IC increases very little with VCE. The reciprocal of the slope of the linear part of the curve gives the value of output resistance.