Common base - Definition and Overview

Common base in Unification Thought refers to thoughts, feelings and aims held in common by two beings. By virtue of the common base, the two beings are able to engage in give and take when prompted by the universal prime force.

See:

• subject and object

Move this to its own article, please.

In electronics, common base refers to a type of bipolar transistor circuit in which a transistor is connected such that its base terminal is wired to the 0 volt or "common" rail of the circuit (or can be considered so for AC signals). This arrangement is relatively uncommon, but is occasionally employed for amplifiers that require an unusually low input impedance, or for VHF and UHF amplifiers where the fact that the output circuit only passes through a single PN junction rather than the two junctions of a common emitter amplifier gives a crucial advantage.

Characteristics

Inherent voltage gain:

With C_E:

<math>

g_m (R_C || R_{load}) <math>

Input resistance:

<math>

R_E || {r_\pi \over 1 + \beta_0} <math>

Current gain:

<math>

A_{vm} {r_{in} \over R_{load}} <math>

Output resistance:

<math>

R_C <math>

Transistor amplifiers

• Common emitter
• Common collector
• Common base
• Common source
• Common drain
• Common gate