Deep Dive: E6B11
The correct answer is A: Forward DC bias current. What is used to control the attenuation of RF signals by a PIN diode is forward DC bias current. PIN diode attenuation is controlled by forward bias current. For amateur radio operators, this is important for RF switching. Understanding this helps when using PIN diodes.
Why Other Answers Are Wrong
Option B: Incorrect. Variable RF reference voltage isn't used - forward DC bias current controls attenuation. RF reference voltage isn't used. Option C: Incorrect. Reverse voltage larger than RF signal isn't used - forward DC bias current controls attenuation. Reverse voltage isn't used. Option D: Incorrect. Capacitance of RF coupling capacitor isn't used - forward DC bias current controls attenuation. Coupling capacitor isn't used.
Exam Tip
PIN diode attenuation control = forward DC bias current. Think 'P'IN 'D'iode 'A'ttenuation = 'F'orward 'D'C 'B'ias. PIN diode attenuation is controlled by forward bias current. Not RF reference voltage, not reverse voltage, not coupling capacitor - just forward DC bias current.
Memory Aid
PIN diode attenuation control = forward DC bias current. Think 'P'IN 'D'iode = 'F'orward 'B'ias. PIN diode attenuation is controlled by forward bias current. Important for RF switching.
Real-World Example
Controlling the attenuation of RF signals by a PIN diode: Forward DC bias current is used. By varying the forward bias current, you can control how much the PIN diode attenuates the RF signal. This is what's used - forward DC bias current.
Source & Coverage
Question Pool: 2024-2028 Question Pool
Subelement: E6B
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 E6B topic.