Yhteisemitterikytkennän

Yhteisemitterikytkentä is a fundamental electronic circuit configuration used with bipolar junction transistors (BJTs). In this setup, the emitter terminal of the transistor is common to both the input and output circuits. This means that the input signal is applied between the base and emitter, and the output signal is taken between the collector and emitter. The emitter itself is typically connected to a common reference point, often ground or a negative voltage rail.

The common emitter configuration is widely used because it offers significant voltage gain and current gain. It inverts the input signal, meaning a positive-going input voltage results in a negative-going output voltage, and vice-versa. This inversion is a characteristic property of the common emitter amplifier. The input impedance of a common emitter amplifier is generally moderate, while its output impedance is also moderate.

This configuration is versatile and can be employed in a variety of applications, including audio amplifiers, switching circuits, and signal amplification stages in more complex electronic systems. The performance characteristics, such as gain and bandwidth, can be adjusted by modifying external components like resistors and capacitors within the circuit. Understanding the common emitter configuration is crucial for analyzing and designing many analog electronic circuits.