window detector

File:Fensterkomperator.svg

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.{{cite book|author1=Ramón Pallás-Areny|author2=John G. Webster|title=Analog Signal Processing|url=https://books.google.com/books?id=JpVk-x-UGroC&pg=PA287|year=1999|publisher=John Wiley & Sons|isbn=978-0-471-12528-0|pages=287–}} It employs two comparators to detect over-voltage or under-voltage.{{cite book|author=Bali|title=Linear Integrated Circuits|url=https://books.google.com/books?id=qm9QCvyiF2MC&pg=PA155|year=2008|publisher=Tata McGraw-Hill Education|isbn=978-0-07-064807-4|pages=155–}}

Each single comparator detects the common input voltage against one of two reference voltages, normally upper and lower limits.{{cite book|author=Steve Ciarcia|title=Ciarcia's Circuit Cellar|url=https://books.google.com/books?id=fBuiNpYlyHcC&pg=RA1-PA92|year=1990|publisher=Circuit Cellar|isbn=978-0-07-010969-8|pages=1–}} 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.{{cn|date=November 2016}}