Deep Dive: E6A05
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.
Why Other Answers 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.
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 Example
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.
Source & Coverage
Question Pool: 2024-2028 Question Pool
Subelement: E6A
Reference: 2024-2028 Question Pool · E6 - Circuit Components
Key Concepts
Verified Content
Question from the official FCC Extra Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the E6A topic.