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 Plan The load line The operating point Recognizing saturation The transistor switch Worksheet No. 4 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 10 - Large Signal Amplifier Third Evaluation

#### The operating point

Every transistor circuit has a load line. If the base resistance is given you can also calculate the current and voltage for the operating point.

Ex: Calculate the operating point (Q-point)

Fig. 4-4: Base biased CE connection

IC = βdc * IB = 100 * 29μA = 2.9 mA

VCE = VCC - (IC * RC) = 15V - (2.9 mA * 3KΩ) = 6.3V

By plotting IC (2.9 mA) and VCE (6.3V), we get the operation point ----> Q-point (quiescent point).

Fig. 4 - 5: Collector curve with load line and Q - point

HO: Draw the load line and Q-point.

Fig. 4-6: base biased CE connection, β=50

Solution:

IC = IB * β = 2.15 mA

VCE = VCC - (RC * IC)= 5.7V

VCE (cut) = VCC = 3.0V