Window detector

A window detector circuit, also called window comparator circuit or dual edge limit detector circuits is used to determine whether an unknown input is between two precise reference threshold voltages.^[1] It employs two comparators to detect over-voltage or under-voltage.^[2]

Each single comparator detects the common input voltage against one of two reference voltages, normally upper and lower limits.^[3] Outputs behind a logic gate like AND detect the input as in range of the so-called "window" between upper and lower reference.

Window detectors are used in industrial alarms, level sensor and controls, digital computers and production-line testing.^{[citation needed]}

If U_in is greater than U_refbot and U_in is lower than U_reftop then both comparators' outputs will swing to the logical high and turn on the AND gate output.

• Comparator
• Operational amplifier
• 555 timer IC

• Tietze, Ulrich; Schenk, Christoph (1993). Halbleiter-Schaltungstechnik (10th ed.). Springer. pp. 190–191. ISBN 3-540-56184-6.