Question
Which trigger mode is most effective when using an oscilloscope to measure a linear power supply’s output ripple?
Answer Options
- A) Single-shot
- B) Edge
- C) Level
- D) Line
Correct Answer: D
Explanation
When measuring the output ripple of a linear power supply (the small amount of AC voltage remaining after rectification and filtering), the ripple frequency is directly related to the input AC line frequency (50 Hz or 60 Hz). For example, a full-wave rectified 60 Hz line produces a 120 Hz ripple. To measure and display this ripple accurately, the oscilloscope needs a stable, synchronized timing reference.
Since the ripple is directly synchronous with the AC power line frequency, the most effective trigger mode is the Line trigger. This mode uses the power line frequency as the stable trigger source, locking the display to the ripple frequency and providing a perfectly stable, non-drifting image of the output ripple waveform for measurement.
This topic was automatically created to facilitate community discussion about this exam question. Feel free to share study tips, memory tricks, or additional explanations!