# Common emitter BJT Amplifier - maximum input voltage

• etf
In summary, the circuit has a β value of 100, VCE saturation of 0.2V, VBE of 0.7V, and λ->0. After completing DC analysis, the results show IB=18.05μA, IC=1.805mA, IE=1.823mA, VCE=4.658V>VCEsaturation=0.2V, gm=0.06943, rCE=∞ Ω, rpi=1.44kΩ. After completing AC analysis, the results show Av=-115.7, Ai=72.23, Rin=1.040kΩ, Rout=1.67kΩ. To avoid
etf
Here is my circuit:
β=100, VCEsaturation=0.2V, VBE=0.7V, λ->0, VT=26mV

After completing DC analysis I got these results :
IB=18.05μA, IC=1.805mA, IE=1.823mA, VCE=4.658V>VCEsaturation=0.2V, gm=0.06943, rCE=∞ Ω, rpi=1.44kΩ.
After completing AC analysis I got Av=-115.7, Ai=72.23, Rin=1.040kΩ, Rout=1.67kΩ.
How to calculate maximum input voltage for proper amplification (without distortion I mean) ?

Last edited:
etf said:
Here is my circuit:
β=100, VCEsaturation=0.2V, VBE=0.7V, λ->0, VT=26mV

View attachment 68124

After completing DC analysis I got these results :
IB=18.05μA, IC=1.805mA, IE=1.823mA, VCE=4.658V>VCEsaturation=0.2V, gm=0.06943, rCE=∞ Ω, rpi=1.44kΩ.
After completing AC analysis I got Av=-115.7, Ai=72.23, Rin=1.040kΩ, Rout=1.67kΩ.
How to calculate maximum input voltage for proper amplification (without distortion I mean) ?

What are your thoughts on this? You have calculated the gain, and you have an idea of where saturation is -- how can you use this? Is the output centered naturally between saturation and cutoff? If not, that will decrease the range of signals that can be passed without distortion.

I know that Q point of BJT should lie in middle of load line for maximum amplification and if input voltage v(t) is too high then BJT will operate in saturation and cutoff and therefore there will be distortion. I'm still not sure how to use this fact for my calculation :(

Last edited:

## What is a common emitter BJT amplifier?

A common emitter BJT (bipolar junction transistor) amplifier is a type of electronic circuit that uses a BJT transistor to amplify a small AC input signal to a larger output signal. It is commonly used in audio amplifiers and other electronic devices.

## What is the maximum input voltage for a common emitter BJT amplifier?

The maximum input voltage for a common emitter BJT amplifier is determined by the voltage rating of the BJT transistor and other components in the circuit. It is important to choose components with appropriate voltage ratings to prevent damage to the circuit.

## Why is the maximum input voltage important in a common emitter BJT amplifier?

The maximum input voltage is important because exceeding it can cause the BJT transistor to enter saturation or breakdown, which can damage the circuit. It is important to select components and design the circuit in a way that ensures the input voltage stays within the maximum limit.

## How can I calculate the maximum input voltage for a common emitter BJT amplifier?

The maximum input voltage can be calculated by considering the voltage rating of the BJT transistor and other components in the circuit, as well as the amplification factor of the BJT amplifier. It is also important to consider any voltage limitations of the power supply used in the circuit.

## Can the maximum input voltage for a common emitter BJT amplifier be exceeded?

Exceeding the maximum input voltage can lead to damage of the circuit and should be avoided. However, some amplifiers may have built-in protection mechanisms to prevent damage from exceeding the maximum input voltage. It is important to refer to the datasheet or consult with a professional when designing and operating a common emitter BJT amplifier.

Replies
16
Views
3K
Replies
8
Views
3K
Replies
19
Views
3K
Replies
25
Views
8K
Replies
6
Views
11K
Replies
5
Views
2K
Replies
4
Views
2K