High Frequency Response of BJT | Multistage Amplifier Part 2 | Electronic Devices and Circuits 2 | Summary and Q&A

TL;DR
Learn about the high frequency response of BJT amplifiers and how to calculate the higher cutoff frequency.
Key Insights
- ✋ BJT amplifiers have capacitances that affect their high frequency response.
- ✋ Certain capacitances become short circuits at high frequencies, while others form stray capacitances.
- ⚡ The higher cutoff frequency needs to be determined to design a BJT amplifier with high voltage gain.
- ✋ The AC equivalent model helps in analyzing the high frequency response using RC circuits.
- ✋ Calculating the higher cutoff frequency involves considering the total capacitance at the input and output side of the AC equivalent model.
- ✋ The minimum value of the higher cutoff frequency is chosen as the desired cutoff frequency for the amplifier design.
- ✋ Understanding the high frequency response of BJT amplifiers is important for circuit design and analysis.
Transcript
Read and summarize the transcript of this video on Glasp Reader (beta).
Questions & Answers
Q: What happens to the capacitances in a BJT amplifier at very high frequencies?
At high frequencies, certain capacitances become short circuits, while others form stray capacitances.
Q: What are the capacitances responsible for the higher frequency response in a BJT amplifier?
The capacitances between the base and collector, collector and emitter, and base and emitter are responsible for the higher frequency response.
Q: How can we model the high frequency response of a BJT amplifier?
An AC equivalent model can be used, where certain capacitances are considered and the resistor-capacitor (RC) circuit is analyzed.
Q: How can we calculate the higher cutoff frequency of a BJT amplifier?
The higher cutoff frequency can be calculated by determining the total capacitance at the input and output side of the AC equivalent model and using the formula 1/2πRC.
Summary & Key Takeaways
-
BJT amplifiers have capacitances that affect their high frequency response.
-
At high frequencies, certain capacitances become short circuits, while others form stray capacitances.
-
To design a BJT amplifier with high voltage gain without damaging the BJT, the higher cutoff frequency needs to be determined.
Share This Summary 📚
Explore More Summaries from Ekeeda 📚





