When you simply connect an oscilloscope to a signal, the screen may show a WAveform that appears unstable, jittery, or rolling. This happens because the scope doesn’t know when to start drawing each WAveform—it just keeps refreshing as data comes in. That’s where the trigger comes in. The trigger tells the oscilloscope when to begin drawing the WAveform on the screen. It locks the display to a specific event—like when the signal crosses a certain voltage level going up (rising edge) or down (falling edge). By doing this, it ensures that each sweep starts a ...