In digital circuits, a runt pulse
is a narrow pulse
due to non-zero rise and fall times of the signal, does not reach a valid
high or low level. A runt pulse may occur when switching between
; or as the result of a race condition
in which a signal takes two separate paths through a circuit, which may have different delays, and is then recombined to form a glitch
; or when the output of a flip-flop
Some oscilloscopes provide a method for triggering on runt pulses. The oscilloscope triggers when the signal crosses one of two voltage thresholds, but not both.