Title: Lesson
Course: Electronics Theory (IC 102-IC 102) > Section: Web Content

Now that you have a handle on the Q-point of a transistor we can examine different biasing techniques. Different Q-points will set up different types of class's of amplifiers, which will have it's own use and efficiency. You will look at different bias methods and at each methods stability, and examine the voltage divider method more carefully since it is the most common one. Interpreting voltage readings on transistors to identify faults in aid to troubleshooting will be introduced. Also you will be analyzing the three different transistor configurations for voltage and current gains, signal phase relationships (input to output) and signal tracing (input to output) in effort to aid in making your troubleshooting more efficient. The focus here might be on transistor circuits, but determining faults from voltage readings apply to any circuit, so I have found this to be a good foundation.
Reading Assignment:
Volume 3 Chapter 4 Bipolar Junction Transistors (The Common-Emitter Amplifier to the End of Chapter) http://www.ibiblio.org/kuphaldt/electricCircuits/Semi/SEMI_4.html
Electrical Motor Controls for Integrated Systems - Chapter #13 (pgs 380-386)
The video section has more information on transistors and voltage divider biasing, this video should also be a guide to help with the homework for the week.
After you have completed the reading assignment, be sure to check out the power points in the Hand-out section.
The Coursework page has a worksheet for calculating the voltages on a voltage divider transistor, which can be applied at any time in the field. The lab assignment is meant to get you familiar with voltages and faults in circuits. Be sure to take note of when the transistor is in saturation and cutoff, can you recognize their states?
Go to the circuit challenges and open up Solid-State Challenge and go to the tab named Basic Transistor Testing. Here you will use an ohmmeter to test transistors for faults and identifying leads, this is a very good learning tool for field checking. You may do this exercise as often as you would like and turn in the one you wish for a score. This is a great fun little exercise that sharpens the skills.
There are several different types of class' of amplifier biasing, in the Forum this week I would like to have some general discussion about them so you get introduced to the different biasing points. Be sure to part take in the discussion topic.