COMMON BASE Meaning and
Definition
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Common base is a term typically used in electronics and telecommunications to refer to a configuration or mode of operation of a bipolar junction transistor (BJT). It is one of the three common configurations used for BJT amplifiers, along with common emitter and common collector. In the common base configuration, the base terminal is common to both the input and output circuits, meaning that the input is applied to the emitter terminal, while the output is taken from the collector terminal.
The name "common base" is derived from the fact that the base terminal is the common terminal between the input and output circuits. This configuration offers unique characteristics and is often utilized in specific applications, such as low-frequency amplification and impedance matching.
In the common base mode, the input signal is coupled to the emitter terminal, which provides a low-impedance connection for the input source. The emitter current controls the collector current, resulting in current amplification. However, the voltage gain is typically lower compared to the other two configurations due to the internal impedance of the input circuit.
The common base configuration finds applications in devices such as preamplifiers, RF (Radio Frequency) amplifiers, and frequency mixers. It is particularly useful in situations where high current gain and voltage gain are not crucial, but a low input impedance and good high-frequency response are desired.
In summary, the common base configuration of a bipolar junction transistor refers to a mode of operation where the base terminal is common to both input and output. It is employed in specific situations where characteristics such as low input impedance, modest voltage gain, and good high-frequency response are desired.
Etymology of COMMON BASE
The word "common" originates from the Latin word "communis", which means "belonging to or shared by all". It later evolved in Old French as "comun" and in Middle English as "common". "Base" comes from the Latin word "basis", meaning "support" or "foundation". In a mathematical or scientific context, "base" refers to a fundamental or starting point. When used together, "common base" refers to a shared or common starting point or foundation. In various fields such as mathematics, physics, electronics, and computer science, "common base" is often used to describe a specific configuration or relationship.
