Understanding DSO Time Scale Control

In a Digital Storage Oscilloscope (DSO), the time scale refers to how the horizontal axis (x-axis) represents time. Adjusting this scale allows you to view more of the signal over a longer duration (slowing down the time base) or to examine a shorter segment of the signal in greater detail (speeding up the time base).

The primary function of controlling the time scale, which involves either increasing or decreasing the duration displayed per horizontal division, is managed by specific controls on the oscilloscope.

Analyzing Oscilloscope Control Functions

Let's examine the function of each control mentioned in the options to understand how they affect the waveform display:

• Vertical Control: This function adjusts the amplitude or voltage scale of the waveform. It determines how much vertical space on the screen represents a specific voltage level (e.g., Volts per division). Changing the vertical control affects the waveform's height, not its duration along the horizontal axis.
• Trigger Control: The trigger system stabilizes the display by initiating the waveform sweep at a specific point in the signal (e.g., when the signal crosses a certain voltage level). While crucial for obtaining a stable waveform, it doesn't directly change the time scale (time per division).
• Cursor: Cursors are measurement tools overlaid on the waveform display. They are used to measure specific voltage levels or time intervals between points on the waveform. Cursors help in analysis but do not alter the fundamental time scale settings of the oscilloscope.
• Horizontal Control: This is the control specifically designed to adjust the time base of the oscilloscope. By adjusting the horizontal control (often labeled "Sec/Div" or similar), you change the amount of time each horizontal division represents. Increasing the value makes each division represent more time (slowing down the sweep, effectively decreasing the displayed time scale for a fixed screen width), and decreasing the value makes each division represent less time (speeding up the sweep, effectively increasing the displayed time scale). Therefore, the horizontal control is used to increase or decrease the time scale of a waveform.

In summary, to adjust how fast or slow the waveform appears across the screen by changing the time duration represented by each horizontal division, you need to use the Horizontal Control.