On a standard oscilloscope, which selector control lets you use the graticule’s major and minor time divisions to determine a waveform’s period and frequency?

Introduction:
Oscilloscopes display voltage versus time using a calibrated grid (graticule). Correctly choosing the horizontal time scale is crucial for measuring period, frequency, and timing relationships like pulse width and rise time.

Given Data / Assumptions:

• A general-purpose analog or digital oscilloscope with a timebase control labeled in time per division.
• Graticule with major and minor divisions uniformly spaced.
• Stable triggered display of the waveform.

Concept / Approach:
The time/cm (time/div) control sets the horizontal scale, specifying how much time each division represents. By counting divisions that span one period of the waveform and multiplying by the time/div setting, you obtain the period; the reciprocal gives frequency.

Step-by-Step Solution:
Set time/div to a value that displays several cycles clearly.Count the number of horizontal divisions for one complete cycle.Compute period: T = (divisions) * (time/div).Compute frequency: f = 1 / T.

Verification / Alternative check:
Compare with automatic frequency readout (if available) or use cursors to measure time between peaks; both methods should agree with the manual time/div approach within instrument accuracy.

Why Other Options Are Wrong:

• Focus and intensity: Adjust trace sharpness and brightness, not time scaling.
• Volts/cm: Vertical scale used for amplitude measurements.
• Trigger level: Stabilizes the display but does not set time per division.

Common Pitfalls:

• Mistaking seconds/div for milliseconds/div or microseconds/div; always check units.
• Measuring an incomplete cycle due to incorrect triggering.

Final Answer:
time/cm control