Oscilloscope Y-gain determines signal voltage from trace divisions

Steps:

• Identify Y-gain setting: 2 V per division on the vertical scale.
• Measure vertical trace span for AC signal: 3 divisions peak-to-peak (from waveform peak to trough).
• Calculate peak-to-peak voltage: 3 divisions × 2 V/division = 6 V.
• Determine AC amplitude: peak voltage is half of peak-to-peak, so 6 V / 2 = 3 V.

Why A is correct:

• AC signals on oscilloscopes display peak-to-peak deflection; amplitude is defined as peak voltage, yielding 3 V for a 3-division span at 2 V/division.

Why the others are wrong:

• B: Assumes 6 V amplitude, which would span 6 divisions peak-to-peak, not 3.
• C: DC signal shows a flat line at voltage level; 3 V would be 1.5 divisions from zero, not a waveform.
• D: DC 6 V would position the line at 3 divisions from zero, indicating steady voltage, not oscillating trace.

Final answer: A