\[A_v=-g_mR_C\]
Variables
Avvoltage gain
gmtransconductance (S)
Rccollector resistor (Ω)
Description
What is this formula?
The Common Emitter Voltage Gain formula calculates the small-signal voltage gain of a common emitter transistor amplifier. This configuration provides high voltage amplification and phase inversion.
When to use it
Use this formula when analyzing or designing BJT transistor amplifiers operating in small-signal conditions.
Example
A transistor amplifier has a transconductance of 0.04 S and a collector resistor of 2.2 kΩ.
Given:
gm = 0.04 S
Rc = 2200 Ω
Formula:
Av = -gm Rc
Substitution:
Av = -(0.04)(2200)
Result:
Av = -88
The amplifier has a voltage gain of -88, indicating signal inversion.
Applications
Audio amplifiers, RF amplifiers, analog signal amplification, transistor preamplifiers, and electronic communication circuits.