Which trigger produces a deadband, preventing output switching ON and OFF as the input crosses the threshold?

• A. Schmidt
• B. Schmitt trigger
• C. Monostable
• D. Latching

Answer: (A)

A deadband comes from a feature called hysteresis, where the device uses two different switching points for rising versus falling input. A Schmitt trigger is designed with positive feedback so the input must cross a higher threshold to turn the output on and a lower threshold to turn it off. That gap between the two thresholds means small fluctuations or noise near the threshold won’t cause the output to chatter; the signal has to move far enough in the appropriate direction to switch. Some people spell it as Schmidt trigger, but the standard name is Schmitt trigger. Monostable and latching devices behave differently: a monostable produces a single pulse in response to a trigger, and a latching holds its state until reset, neither of which inherently provide a deadband for crossing the threshold.