7.1.3—The use of the time-base and y-gain of a cathode-ray oscilloscope (CRO) to
- Syllabus
- 9702–2028–2029
- Objective
- 7.1.3
- Level
- AS
A CRO converts time-base and vertical scale settings into time and voltage measurements
On a cathode-ray oscilloscope, the time-base sets horizontal time per division and the y-gain sets vertical voltage per division.
Count divisions between peaks or from the baseline, then multiply by the relevant scale. Use a stable trigger before reading a period.
Four horizontal divisions at 2 ms div⁻¹ give a 8 ms period and frequency 125 Hz.
The vertical height measures voltage, not time; confusing the two scales produces plausible but wrong frequencies or amplitudes.
ConceptA-Level CAIE Physics AS