Home
Back
Common Emitter Amplifier Gain Formula:
| From: | To: |
The Common Emitter Amplifier is one of the three basic single-stage bipolar junction transistor (BJT) amplifier topologies. It provides both voltage and current gain, making it one of the most widely used transistor amplifier configurations.
The calculator uses the common emitter amplifier gain formula:
Where:
Explanation: The negative sign indicates a 180-degree phase shift between input and output signals. The gain is determined by the ratio of collector resistance to emitter resistance.
Details: Accurate gain calculation is crucial for designing amplifier circuits, predicting signal amplification, ensuring proper circuit performance, and avoiding signal distortion in electronic systems.
Tips: Enter collector resistance and transistor emitter resistance in ohms. Both values must be positive and non-zero for accurate calculation.
Q1: What does the negative sign in the gain formula mean?
A: The negative sign indicates that the common emitter amplifier produces a 180-degree phase shift between the input and output signals.
Q2: What are typical values for R_C and r_e?
A: Typical R_C values range from 1kΩ to 10kΩ, while r_e is typically around 25-50Ω depending on the transistor and operating conditions.
Q3: Why is the common emitter configuration so popular?
A: It provides both voltage and current gain, has high input impedance, and offers good overall performance for most amplification applications.
Q4: What factors affect the actual gain in practical circuits?
A: Load resistance, source impedance, temperature, transistor characteristics, and bypass capacitors can all affect the actual circuit gain.
Q5: When should I use a common emitter amplifier?
A: Use it when you need both voltage and current amplification, such as in audio amplifiers, RF amplifiers, and general-purpose signal processing circuits.