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

voltage Voltage, also known as electric pressure, electric tension, or (electric) potential difference, is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge to m ...

s. It employs two

comparator In electronics, a comparator is a device that compares two voltages or currents and outputs a digital signal indicating which is larger. It has two analog input terminals V_+ and V_- and one binary digital output V_\text. The output is ideally : ...

s to detect over-voltage or under-voltage. Each single comparator detects the common input voltage against one of two reference voltages, normally upper and lower limits. 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 Level sensors detect the level of liquids and other fluids and fluidized solids, including slurries, granular materials, and powders that exhibit an upper free surface. Substances that flow become essentially horizontal in their containers (or ...

and controls, digital

computers A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations (computation) automatically. Modern digital electronic computers can perform generic sets of operations known as programs. These programs ...

and production-line testing.

Function

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.

Function

See also

References

Further reading