Due Friday 2019-02-08 at the start of class. Submit either on paper or via Blackboard.

Figure 1. CB + EF Amplifier
Figure 2. Transistor amplifier view
Figure 3. Small-signal amplifier view

## 1. Amplifier parameters

Treat the circuit of Figure 1, “CB + EF Amplifier” as two amplifiers in cascade. From the DC bias conditions, compute the 3 main parameters of each sub-amplifier Rin, Rout, and open-circuit voltage gain Av0. Use the Tour Book Tables 4, 5, and 5 to compute these numbers. Notice that the collector current $I_C$ in Table 4 is in UPPERUPPER form — the DC value (from `hw05`).

Find the following numerical parameters for Figure 3, “Small-signal amplifier view” that correspond to Figure 1, “CB + EF Amplifier”.

Param Value (unit)

Rin1

Rout1

AV0_1

Rin2

Rout2

AV0_2

Rin (blue)

Rout (blue)

AV = vout / vin

## 2. Simulation

Build a CircuitLab or LTspice simulation of both of Figure 1, “CB + EF Amplifier” and Figure 3, “Small-signal amplifier view” circuits. Set the component values for Figure 1, “CB + EF Amplifier” to those found in Section 1, “Amplifier parameters”.

Use a DC operating point simulation to verify that the DC node voltages match your hand calculations and measurements from `hw05` (`.op` in LTspice or `DC` in CircuitLab).

Simulate the frequency response of each of the circuits and plot the magnitude of both `out` node voltages. They will be between 35 and 40 dBV and be nearly the same until around 1 MHz where the “real” circuit’s output amplitude begins to decrease.[1]

• Turn in a single figure showing the magnitude vs. frequency for both circuits.

1. $20 \log_{10}\left(\dfrac{x}{1\,\mathrm{Vrms}}\right) = x\,\mathrm{dBV}$ and $10^{x\,\mathrm{dBV}/20} = x\,\mathrm{Vrms}$