3.3.2 output Characteristics of the Common-Emitter Configuration To determine the output characteristics of any configuration, we need to examine the relationship between the output current and the output voltage, and the effect of the input voltage or current on this relationship. Referring to Figure 3-8, the output current is the lc, the output voltage is VCE, and the input current is la. Thus, imagine a test circuit as illustrated in Figure 3-8 with adjustable supply voltages vas and Vce. so that we can control the input current Is and the output voltage Vo