🔍 Key Concepts
• Amplifier bias point and how it relates to the conduction angle (portion of the signal cycle during which the transistor conducts)
• Differences among Class A, B, AB, and C in terms of how much of the input waveform they conduct
• Relationship between bias beyond cutoff and very small conduction angle (less than 180°)
💭 Think About
• For each class (A, B, AB, C), think about what fraction of the input signal cycle the device conducts current.
• Which amplifier class is associated with high efficiency but significant distortion, often used in RF (radio frequency) transmitters rather than audio?
• If the bias is set well beyond cutoff, will the device conduct for more or less than half of the input cycle?
✅ Before You Answer
• Review which class conducts for 360°, which for 180°, which for between 180° and 360°, and which for less than 180° of the input cycle.
• Match the description "bias well beyond cutoff" to the class that conducts the smallest portion of the cycle.
• Eliminate the classes that are known for low distortion and more linear operation, since those require conduction over most or all of the waveform.