A trigger is a defined voltage threshold or pulse edge that tells a circuit or measurement device to execute an action. In oscilloscopes, the trigger synchronizes the horizontal sweep to the incoming signal, stabilizing repeating waveforms on the screen or capturing transient glitches. In digital logic, a trigger pulse forces a flip-flop or timer to change state.
Set the scope trigger to a falling edge at two volts so we can catch the exact moment the power rail drops out.
Related terms
Edge-triggered
A digital input that responds only to the transition of a clock signal.
Level-triggered
Describing a logic circuit that responds to inputs as long as the clock signal is at a specific voltage.
Schmitt trigger
A comparator circuit that uses positive feedback to create hysteresis, converting noisy analog signals into clean digital pulses.