Question

Amplifier design: You can use a 2N2222 npn BJT (β=200) for your design. V+=12V, V-=-12V. Describe each step of your solution clearly in your report and include the relevant schematic, result graph and analysis. a. Common Emitter amplifier circuit: Design a Common Emitter circuit with AC voltage gain 110 (40dB), fL=5kHz, fH=35MHz. i.

Answer 1

To design a common emitter amplifier circuit with a 2N2222 npn BJT, you need to determine the required AC voltage gain, calculate the values of the input and output coupling capacitors, and determine the values of the bias resistors. A detailed report can include calculations, circuit diagrams, and analysis to illustrate the design process.

Step-by-step explanation:

To design a common emitter amplifier circuit using a 2N2222 npn BJT, we can follow these steps:

1. First, determine the required AC voltage gain, which in this case is 110 (40 dB).
2. Next, calculate the values of the input and output coupling capacitors, C1 and C2, respectively. The low-frequency cutoff frequency (fL) is given as 5 kHz, so the value of C1 can be calculated using the formula C1 = 1 / (2πfLC1). For example, if we choose a value of 1 μF for C1, the cutoff frequency would be approximately 3.18 kHz. Similarly, the high-frequency cutoff frequency (fH) is given as 35 MHz, so the value of C2 can be calculated using the formula C2 = 1 / (2πfHC2). For example, if we choose a value of 10 pF for C2, the cutoff frequency would be approximately 477.16 kHz.
3. Then, calculate the values of the bias resistors, RC and RE. The bias resistors help establish the DC operating point of the amplifier. The emitter resistor (RE) can be calculated using the formula RE = Vth / IE, where Vth is the thermal voltage and IE is the desired emitter current. For example, if we choose a value of 1 kΩ for RE and assume a desired emitter current of 2 mA, the thermal voltage can be calculated as Vth = RE * IE = 1 kΩ * 2 mA ≈ 2 V. The collector resistor (RC) can be chosen based on the desired collector current and the voltage across RC, which should be half of the supply voltage (V+ or V-). Let's assume a desired collector current of 1 mA, so RC = (V+ - Vrcsat) / Ic, where Vrcsat is the saturation voltage of the collector-emitter junction. For a 2N2222 transistor, Vrcsat is typically around 0.2 V. If we take V+ = 12 V, then RC ≈ (12 V - 0.2 V) / 1 mA = 11.8 kΩ.

This is a basic outline of the design process for a common emitter amplifier circuit. It's important to note that other components, such as bypass capacitors and input impedance matching, should also be considered for a complete design. To create a report with the relevant schematic, result graph, and analysis, you can include detailed calculations and circuit diagrams with the values determined in the steps above. This will help demonstrate the design process and provide a clear understanding of the amplifier circuit.