Time-base measures sweep speed in CRO

Steps:

• Recall CRO displays waveforms with horizontal time axis and vertical amplitude.
• Identify time-base as circuit generating horizontal deflection at constant speed.
• Note calibration sets time per screen division (e.g., 1 ms/div) for waveform timing.
• Compare options: D matches time per division definition.

Why D is correct:

• Time-base is defined as time interval per horizontal screen division, enabling accurate period/frequency measurement via formula T = n × (time/div), where n is divisions per cycle.

Why the others are wrong:

• A confuses with reciprocal (frequency/div), not time scale.
• B inverts scale, describing divisions per frequency, irrelevant to time-base.
• C omits unit (time), making it incomplete and vague.

Final answer: D