 An oscilloscope sweep mode controls if or when it should display a waveform in relation to its trigger conditions being met. Auto-sweep will display a waveform as soon as possible, even if no trigger condition has been met, which can get messy. Normal sweep will display whenever a trigger condition is met. If the signal stops meeting the trigger condition, the last triggering waveform will remain on screen. Finally, in single sweep mode, the scope displays the wave only the first time the trigger condition is met. That single snapshot will remain on the display until manually reset via the Run Stop button.