                            Amplifier Teaching Aid (GTZ, DED; 86 pages)  Preface  Introduction  Lesson 1 - Semiconductor Review  Lesson 2 - Bipolar Transistor  Bipolar Transistor II  First Evaluation  Lesson 4 - Transistor Fundamentals  Lesson 5 - Transistor Biasing  Lesson 6 - Transistor Biasing II  Second Evaluation  Lesson 7 - Small Signal Amplifier  Lesson 8 - Small Signal Amplifier II  Lesson 9 - Small Signal Amplifier III   Lesson Plan    Other configurations    Frequency response of an amplifier    The AC load line   Handout No. 2   Worksheet No. 9  Lesson 10 - Large Signal Amplifier  Third Evaluation

In previous lessons we used the dc load line to analyze biasing circuits. But an amplifier sees two loads, a dc load and a ac load. Now we will use the ac load line to understand the large signal operations. Fig. 9-2: CE amplifier

DC values: VB = 1.8V, VE = 1.1V, IE = 1.1 mA, VC = 6.04V VCC = 10V, VCE = 4.94V The following process shows you an easy method to get the ac load line:

1. Draw the dc load line VCE (cut) = VCC - VE = 8.9V

2. Calculate and draw the Q point

IC = 1.1 mA

VCE = 6.04V

3. Draw a -temporary ac load line

VCE (cut) = VCC 4. Construct the ac load line

- parallel to the temporary ac load line
- passing the Q point Fig. 9-3: Construction of an ac load line   