Common-Emitter and Common-Collector Transistor Amplifier Calculator for High-frequency Operation
Analysis of the bipolar transistor amplifier at low-frequency is relatively easy, and several calculators exist online that do a good job. For high-frequency operation, there are fewer references available. For my projects, I like to build a reference spreadhseet where everything is in one place. This allows me more flexibility in optimizing the circuit, and is much faster than simulating with LTSpice or similar package. Furthermore, constructing such a tool is a great way of gaining more insight into how the circuit works, and how each of the parameters affects performance. The two amplifier circuits covered in this spreadsheet are depicted in Figure 1 and 2. Figure 1 is the Common-Emitter amplifier and is useful for relatively high gain applications with moderate input and output impedance. The Common Collector circuit in Figure 2, has a gain close to 1 and is useful as a buffer circuit with its low output impedance and moderate to high input impedance.
For more detail: High- Frequency Transistor Amplifier Calculator