Comparators

A fundamental component of logic-driven electronic circuits, comparators play a basic but essential role in electronics today. At RS, we offer a huge range of amplifiers and comparators to suit a wide spectrum of circuit design projects and developments.

Featuring hundreds of options from trusted manufacturers including Diodes Inc., Microchip Technology Inc., and ON Semiconductor, we are proud to supply a great value range of high-quality operational amplifiers and voltage comparators. All are available in bulk-buy quantities as per your personal or organizational requirements.

You can start shopping our range of comparators by using the filters on the left-hand side of the page or read on to find out more about comparators and their function, uses, and types.

What are comparators?

A comparator circuit compares two voltage or current inputs and provides an output based on which is greater (or lesser, as per the requirements of the circuit). A comparator has two analog input terminals (V+ and V-) and one binary digital output.

Comparators are typically classified as either operational amplifiers (op-amp comparators or comparator amplifiers) or voltage comparators. While the two are very similar in their operation and purpose, there are a few small schematic differences in the output structure.

Voltage comparators can only sink current while op-amps have a complementary output that allows current to flow in either direction. Put more simply, operational amplifiers can be used with negative feedback, while voltage comparators either use positive feedback or no feedback at all to switch the output between two saturated states.

The fundamental purpose of comparator devices is to check whether an input has reached a predetermined value or if an input voltage falls above or below a reference figure. If, for example, the input falls below the given reference figure, the comparator can flag the condition.

How does a comparator circuit work?

A comparator amplifier circuit compares two voltages and outputs either a 1 (the voltage at the positive side) or a 0 (the voltage at the negative side) to indicate which is larger. The comparator circuit compares these two voltages via two input pins and turns on the output when identifying either a difference or similarity.

Dedicated voltage comparators are typically faster than op-amp comparators and can also contain additional components such as an accurate internal reference voltage, clock-gated input, and adjustable hysteresis. These precision comparators are effective for amplification of a small input differential, as in less sophisticated comparator circuits nearly equal voltages can produce a non-result (the output voltage will not fall into either logic level). This can be problematic for users seeking accurate results.

What applications are comparators used for?

Comparators are widely used in logic circuits to carry out mathematical operations such as addition, subtraction, integration, and differentiation. They can, for example, be used alongside a thermistor to detect temperature increases or decreases against an established threshold.

Because of their extensive array of uses, comparators are found in most electric circuits. Despite their similarities, op-amps cannot be used directly in voltage comparator circuits but find use in a huge variety of other applications.

What are the different types of comparators?

There are two types of basic comparators to consider - inverting and non-inverting.

Inverting comparators

An inverting comparator is a form of op-amp comparator. Its non-inverting terminal has a reference voltage applied while the input voltage is applied to its inverting terminal. The name inverting comparator is given because the input voltage that must be compared is applied to the inverting terminal.

An inverting comparator will produce one of two values - +Vsat (if the input voltage is less than the reference voltage) or -Vsat (if the input voltage is greater than the reference voltage).

Non-inverting comparators

Following on logically, a non-inverting comparator simply reverses the terminals for the reference voltage and input voltage, applying the input voltage to the non-inverting terminal and the reference voltage to the inverting terminal.

In this instance, the +Vsat value will be displayed if the input voltage is greater than the reference, with the -Vsat displayed for a lower input voltage than the reference.

In the RS catalog, you'll find a wide variety of comparator types that cover different power supply formats, mounting types, and pin counts among other build factors (all of which you can search for specifically via our handy filters).

Some of the comparator types we supply include:

• High-speed CMOS comparators
• Differential amplifier comparators, including dual and quad differential comparators
• High-speed dual comparators
• ECL comparators
• TTL comparators

If you're unsure of which comparator type is suitable for your project, we can always try to help. Contact our team today to get more information.

Get started on your circuit design project with RS

We're proud to be one of North America's largest suppliers of high-quality, bulk-buy electronic components. Whether you're looking for circuitry pieces for a personal project or a mass order to meet your organizational requirements, we're here to help.

Contact the team today if you have any questions about our product catalog. If you'd like to know about getting the most from our products, our expert hub offers plenty of useful information to help you out.