## Description

For the following, use the figure and the simplified NPN model from Section 2.1.1 in AoE. *V _{CC}* = 5V,

*C*=

1µF, and = 100. Use the *npn* Ltspice component for your simulations.

- Select values for
*R*and_{B1}*R*to achieve_{B2 }*V*= 1V and a high-pass corner frequency (_{B}*f*) of 10Hz. You may ignore base current for this step._{3dB} - Choose
*R*and_{C}*R*for a gain of −10V/V (at 10kHz) and a collector current of 1mA. What is the DC value of_{E}*V*?_{CE} - Derive the transfer function for
*V*/_{out}*V*and plot the frequency response (magnitude and phase) in MATLAB/Python._{in} - Perform an AC simulation of the circuit in Ltspice. Export the frequency response data for comparison to the ideal response from Part c (plot them together). Provide reasons for any discrepancies between the two.

# Problem 2: Emitter follower

# Figure 2a. Emitter follower Figure 2b. Small-signal equivalent circuit

Use the __Ebers-Moll model __of the BJT and the figures to answer the following questions. *V _{CC}* = 5V,

*I*= 10

_{S}^{−16}, and = 100. When determining input/output resistances, connect a test voltage to the smallsignal circuit and determine the resistance as

*r*=

*v*/

_{test}*i*. Use the

_{test}*npn*Ltspice component for your simulations.

- Design the biasing of the emitter follower (i.e. determine
*V*and_{B}*R*) such that the collector current is 1mA and the DC level of_{E}*V*is 1V. You can do this by hand or use a MATLAB/Python script._{out} - Use the small-signal model (Fig. 2b) to determine the input resistance of the circuit.
- Use the small-signal model (Fig. 2b) to determine the output resistance of the circuit.
- Verify your design in Ltspice and include all relevant SPICE schematics and results in your submission.