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

cb lab2b
Figure 1. CB + EF Amplifier
2 stage transistor amp
Figure 2. Transistor amplifier view
2 stage amp
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)







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 \(10^{x\,\mathrm{dBV}/20} = x\,\mathrm{Vrms}\)