Common-base configuration:

 The common-base that is abbreviated as CB transistor configuration, which is as well termed as the 'grounded base' configuration, is displayed in figure.  In this configuration, the terminal common to both the input and the output of the circuit is the base.

Figure:  Common-Base Transistor Configuration

 The output voltage and input current of the common-base configuration that are the emitter current I_e and the collector-base voltage V_cb, correspondingly, are frequently considered as the independent variables in this circuit. The dependent variables of it, on the other hand, are the emitter-base voltage V_eb (that is the input voltage) and the collector current I_c (that is the output current).  A plot of the output current I_c against the collector-base voltage V_cb for different values of I_e might be drawn for easier analysis of a input or output characteristics of transistor, as displayed in this figure of V_cb-I_c Curves.