Deep Dive: E4A10
The correct answer is D: Line. Which trigger mode is most effective when using an oscilloscope to measure a linear power supply's output ripple is line. Line trigger synchronizes to AC line frequency, ideal for ripple measurement. For amateur radio operators, this is important for test equipment. Understanding this helps when measuring power supply ripple.
Why Other Answers Are Wrong
Option A (Single-shot): Incorrect. Single-shot isn't effective for ripple - line trigger synchronizes to AC line frequency. Single-shot isn't effective. Option B (Edge): Incorrect. Edge trigger isn't as effective - line trigger synchronizes to AC line frequency for ripple. Edge isn't as effective. Option C (Level): Incorrect. Level trigger isn't as effective - line trigger synchronizes to AC line frequency for ripple. Level isn't as effective.
Exam Tip
Oscilloscope trigger for power supply ripple = line trigger. Think 'L'inear 'P'ower 'S'upply 'R'ipple = 'L'ine trigger. Line trigger synchronizes to AC line frequency, ideal for ripple measurement. Not single-shot, not edge, not level - just line.
Memory Aid
Oscilloscope trigger for power supply ripple = line trigger. Think 'L'inear 'P'ower 'S'upply = 'L'ine trigger. Line trigger synchronizes to AC line frequency, ideal for ripple measurement. Important for test equipment.
Real-World Example
Measuring a linear power supply's output ripple with an oscilloscope: Line trigger mode is most effective. Line trigger synchronizes to the AC line frequency (50/60 Hz), which is the frequency of the ripple. This provides a stable display of the ripple waveform. This is the trigger mode - line trigger for ripple measurement.
Source & Coverage
Question Pool: 2024-2028 Question Pool
Subelement: E4A
Reference: 2024-2028 Question Pool · E4 - Amateur Practices
Key Concepts
Verified Content
Question from the official FCC Extra Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the E4A topic.