Visualizing BJT operating modes via simulation

1. Announcements

  • Login to your PC, we are installing / using LTspice today.

  • Check out the syllabus, especially the Grading section.

2. LTspice

2.1. Install and play along

2.2. day02 circuit sim demo

realtime

  • day02 circuit simulation in LTspice

3. CircuitLab

(you should watch this) YouTube video using CircuitLab: Simulating the DC solution of a common-emitter bipolar transistor circuit

4. Thevenin equivalent circuits

(deferred to day04?)

Do you remember how to compute these for a circuit? This was a core ECE 263 topic and is now important to do this correctly (and quickly). Time to practice!

Voc

open-circuit voltage

Isc

short-circuit current

Rth = Rnor = Voc/Isc

or set independent sources to zero and find the equivalent resistance

autoCircuits uses conductance for the Norton equivalent

Generate a circuit to solve from autoCircuits with the following parameters:

  • Get Circuit → Chapters → DC Thevenin-Norton equivalents

  • Numeric - Integer - Medium - No - No - No

  • “Click to generate circuit”

Open the PDF and proceed to find the requested parameters. You should get the answer on the second page exactly.

Generate another problem with parameters:

  • Get Circuit → Chapters → DC Thevenin-Norton equivalents

  • Numeric - Real - Medium - No - No - No