Transition time measures how long it takes a digital signal or switch output to move between defined voltage thresholds, typically 10% and 90% of its final value. It encompasses both rise time and fall time. Fast transition times reduce power dissipation in switching components but can introduce severe electromagnetic interference and ringing if the board traces are not properly matched.
Heard on the job
The transition time on this clock line is too slow, causing the flip-flop to double-trigger on the messy edge.