The Common Emitter configuration is a basic transistor amplifier setup where the emitter terminal of a bipolar junction transistor (BJT) is common to both the input and output circuits. In this arrangement, the input signal is applied between the base and emitter, while the output is taken from the collector and emitter. This configuration is widely used due to its ability to provide significant voltage gain. In a Common Emitter circuit, the output signal is inverted, meaning that when the input signal increases, the output signal decreases, and vice versa. This characteristic makes it useful in various applications, including audio amplifiers and signal processing. The configuration is favored for its simplicity and effectiveness in amplifying weak signals.