🔍 Key Concepts
• Emitter-follower (common-collector) configuration basic behavior
• Relationship between voltage gain, current gain, and power gain in transistor amplifiers
• Typical input and output impedance characteristics of common-emitter, common-base, and emitter-follower stages
💭 Think About
• Think about whether an emitter-follower inverts or nearly copies the input voltage. What does that suggest about its voltage gain compared with 1?
• Consider why emitter-followers are often used as buffer stages between a high-impedance source and a low-impedance load. Which parameter (current, voltage, or power gain) makes them useful for this role?
• Compare the input impedance of common-base, common-emitter, and emitter-follower configurations. Which one is normally chosen when you want to avoid loading the previous stage?
✅ Before You Answer
• Verify which configuration (common-base, common-emitter, or emitter-follower) typically has the highest input impedance and lowest output impedance.
• Check whether the voltage gain of an emitter-follower is significantly greater than 1, approximately 1, or less than 1.
• Confirm which configuration is known for providing high current gain while maintaining a voltage gain close to unity.