Read the passage and answer the question.

A junction diode cannot be used for amplification so another type of semiconductor device, a transistor, is used. It is a three section semiconductor with three sections being the emitter, the collector and the base. Common emitter characteristics of a transistor are graphs that are obtained between voltage and current, when emitter is earthed, base is used as input terminal and collector as the output terminal.

What are output characteristics of this amplifier?

ratio of collector voltage to collector current keeping base current constant.

It is the ratio of small change in output voltage to small change in output current keeping input current constant.