Editing Comparator (section)

===Output type===
[[File:Dynamic Comparator.png|thumb|right|upright=1.35|A low-power CMOS clocked comparator]]

Because comparators have only two output states, their outputs are either near zero or near the supply voltage. Bipolar rail-to-rail comparators have a common-emitter output that produces a small voltage drop between the output and each rail. That drop is equal to the collector-to-emitter voltage of a saturated transistor. When output currents are light, output voltages of CMOS rail-to-rail comparators, which rely on a saturated MOSFET, range closer to the rail voltages than their bipolar counterparts.<ref name="test">{{cite web |id=AN886 |publisher=Maxim Integrated Products |url=http://www.maxim-ic.com/appnotes.cfm/an_pk/886/ |title=Selecting the Right Comparator |url-status=dead |archive-url=https://web.archive.org/web/20080501144538/http://www.maxim-ic.com/appnotes.cfm/an_pk/886/ |archive-date=2008-05-01}}</ref>

On the basis of outputs, comparators can also be classified as [[open-drain]] or [[push–pull output|push–pull]]. Comparators with an open-drain output stage use an external [[pull-up resistor]] to a positive supply that defines the logic high level. Open-drain comparators are more suitable for mixed-voltage system design. Since the output has high impedance for logic high level, open-drain comparators can also be used to connect multiple comparators to a single bus. Push–pull output does not need a pull-up resistor and can also source current, unlike an open-drain output.