How does DC input impedance at the gate of a field-effect transistor (FET) compare with that of a bipolar transistor?
The correct answer is C: An FET has higher input impedance. How does DC input impedance at the gate of a field-effect transistor (FET) compare with that of a bipolar transistor is that an FET has higher input impedance. FET gates have very high input impedance. For amateur radio operators, this is important for transistor knowledge. Understanding this helps when selecting transistors.
Exam Tip
FET vs bipolar input impedance = FET has higher input impedance. Think 'F'ET = 'H'igh input impedance, 'B'ipolar = 'L'ow. FET gates have very high input impedance. Not both low, not FET lower, not both high - just FET higher.
Memory Aid
"FET vs bipolar input impedance = FET has higher input impedance. Think 'F'ET = 'H'igh impedance. FET gates have very high input impedance. Important for transistor knowledge."
Real-World Application
DC input impedance at the gate of an FET compared to a bipolar transistor: An FET has higher input impedance. FET gates are essentially insulated, giving very high impedance, while bipolar transistors have lower input impedance due to base current. This is the comparison - FET has higher input impedance.
Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. They are both low impedance isn't correct - FET has high impedance, bipolar has low. Both low is wrong.
Option B: Incorrect. FET has lower input impedance isn't correct - FET has higher impedance. Lower is wrong.
Option D: Incorrect. They are both high impedance isn't correct - FET has high, bipolar has low. Both high is wrong.
题目解析
The correct answer is C: An FET has higher input impedance. How does DC input impedance at the gate of a field-effect transistor (FET) compare with that of a bipolar transistor is that an FET has higher input impedance. FET gates have very high input impedance. For amateur radio operators, this is important for transistor knowledge. Understanding this helps when selecting transistors.
考试技巧
FET vs bipolar input impedance = FET has higher input impedance. Think 'F'ET = 'H'igh input impedance, 'B'ipolar = 'L'ow. FET gates have very high input impedance. Not both low, not FET lower, not both high - just FET higher.
记忆口诀
FET vs bipolar input impedance = FET has higher input impedance. Think 'F'ET = 'H'igh impedance. FET gates have very high input impedance. Important for transistor knowledge.
实际应用示例
DC input impedance at the gate of an FET compared to a bipolar transistor: An FET has higher input impedance. FET gates are essentially insulated, giving very high impedance, while bipolar transistors have lower input impedance due to base current. This is the comparison - FET has higher input impedance.
错误选项分析
Option A: Incorrect. They are both low impedance isn't correct - FET has high impedance, bipolar has low. Both low is wrong. Option B: Incorrect. FET has lower input impedance isn't correct - FET has higher impedance. Lower is wrong. Option D: Incorrect. They are both high impedance isn't correct - FET has high, bipolar has low. Both high is wrong.
知识点
DC input impedance, Gate of FET, Bipolar transistor, FET has higher input impedance
Verified Content
Question from official FCC Extra Class question pool. Explanation reviewed by licensed amateur radio operators.