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What is a Comparator Circuit?

Keith Koons
Keith Koons

A comparator circuit is a programmable device that monitors electrical currents and performs a specific function based on those readings. This is normally accomplished with two or more sensors that measure the various changes throughout the electrical paths to continuously solve a preset mathematical formula. One of the comparator circuits will always maintain a constant charge at a predetermined electrical frequency while the others will receive varying amounts of current dependent on their intended applications. The device that holds the voltage comparator circuits will function based on the feedback that is given to it, which essentially automates the machinery without further human intervention.

A prime example of a simple comparator circuit can be found within a programmable thermostat. With two separate inputs, three outcomes are achievable at any given time. When the base input becomes lower than the variable, a signal will be sent to the thermostat to activate the cooling feature, and that circuitry will allow that function to occur until both the base and variable are once again equal. At that point, the air conditioner would shut off until further instructions were provided.


If the variable electrical node provided less electrical power than the constant, a signal would be generated to inform the thermostat to activate the heating element. It would remain on until the variables changed once again. Each of these functions are pre-programmed to react differently as the values change, and the comparator circuit design interprets them by analyzing the variable data.

The bit comparator circuit is limited to the number of implemented inputs and the functions that are assigned to each of their corresponding values, so quite a bit of meticulous detail is involved with designing such a device. A comparator circuit diagram will show the circuitry path leading to each of the variables. It is entirely possible to link multiple comparator circuits together to solve quite complex equations within milliseconds. This type of design would be suitable on a device that can be programmed to complete dozens or even hundreds of varying tasks, each of them controlled by the comparator. As long as the voltage remains within the acceptable range of the device, comparator circuits are considered very reliable and the preferred choice in most electronic devices.

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