Due Wednesday 2018-02-21 at the start of class.

1. Reading

Read [AoE] section 2.3.8 Differential amplifiers starting on page 103.

We will analyze and build several ciruits using differential pairs, ending with a complete operational amplifier (!). That circuit will provide a nice bridge to our next course unit about designing with real-world opamps. We will also begin to make heavy use of the Analog Discovery 2’s advanced features for plotting real-time frequency responses (a.k.a. Bode plots).

2. Handout analysis

Analyze the common emitter circuit from Monday’s handout. 2018-09-19 handout

  • This document (amplifier-terms_CE.pdf) is a much better version of what I wrote on the handout in class. The only difference is that I include the full ZE instead of it being bypassed in the handout with the BFC CE. It is also posted in the Class notes G-Drive folder.

Do this analysis using the full circuit analysis and algebra twice, first using the hybrid pi model and then using the T model. Reference Guidebook: § Small-signal models.

For each circuit, find the following small-signal quantities:

  • Amplifier input resistance \(R_{in}\).

  • Amplifier output resistance \(R_{out}\).

  • Amplifier open-circuit voltage gain \(\left(A_{v0}=\dfrac{v_{out}}{v_{in}}\bigg\rvert_{R_L \rightarrow \infty}\right)\). This is without Rload connected.

  • Amplifier loaded voltage gain \(\left(A_v=\dfrac{v_{out}}{v_{in}}\right)\). This is with Rload connected. This should be easy if you think of Thévenin equivalents.

If you do not get the exact same symbolic results: you are not finished, keep going! For a fun(?) third round, try using the Table 6: BJT amplifier types table and get the same answers.

Re-write your solutions into the following format:[1]

  • One side of writing per page.

  • One column of intermixed schematic, math, and text.

  • Near-zero cross-outs or erase marks.


1. I will hand your paper back without grading for you to actually re-write!