Analog comparators are amplifiers that compare the magnitude of voltages at two inputs. An analog comparator is an operational amplifier with negative feedback removed, and with no feedback and very high gain, the output voltage goes to one extreme to the other. In analog comparators, this is generally limited to just outside the ±10 volt limit to avoid any possible damage. Analog-to-digital conversion (ADC) is the method of using a comparator to determine whether or not to turn on binary output. ADCs typically use digital-to-analog converters (DACs) to determine inputs to the comparator. Digital-to-analog conversion is the method of converting digital data to analog form by using a summing amplifier.
Analog comparators, such as a voltage comparator, are an integrated circuit equivalent to an operational amplifier, with two NPN transistors added to the output of each amplifier. The purpose of voltage comparators is to provide digital output from an analog input. Voltage comparators provide high positive or negative voltage, depending on which voltage is higher. Voltage comparators can be used for temperature monitoring by comparing the voltage to a thermostat. Voltage comparators are used in flashing LEDs found in audio system signal level meters, as well as in a wide range of mixed signal sensor circuit applications, used to compare measurements that could be translated into corresponding electrical signals.
Analog comparators are used as key components in A/D converters, and are also used in level detection, on-off controls, clock-recovery circuits, window detectors, and Schmitt triggers. The output stage of analog comparators is wired to be more flexible than that of op-amps. Analog comparators often have a latch that permits strobing the input at the right time and a shutdown function that conserves power when the comparator is not needed. Analog comparators can be configured to use a threshold detector to determine if an input voltage is greater than or less than a given reference voltage.
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