MCP3424 18-Bit ADC-4 Channel with Programmable Gain Amplifier

Jargon buster

Plain-language definitions for the technical terms used above.

ADC

An analogue-to-digital converter reads a changing voltage and turns it into a number the microcontroller can use. It matters when connecting analogue sensors such as light, sound, or variable-resistor sensors.

Differential input

A measurement method where the board reads the voltage difference between two input wires instead of measuring one wire compared with ground. This is useful for small sensor signals and noise reduction, but both input voltages still need to stay within the board’s allowed range.

Gain error

Gain error is a scaling error in which a device's output grows slightly too much or too little across its range, affecting converters, amplifiers and sensors alike. It matters wherever the exact relationship between the input value and the resulting output needs to be accurate.

I2C

I2C is a two-wire communication bus used by many sensors and small modules. It matters because several I2C devices can share the same two wires, but each device needs a compatible address and your controller must support I2C.

microcontroller

A microcontroller is a small computer on a single chip that runs a stored program and controls connected inputs and outputs such as buttons, sensors, displays and communication interfaces. In a device built around one, it is the part that executes the code and coordinates the device's behaviour.

Offset error

Offset error is a small, roughly constant error that remains even when the input or output should be at or near zero, and it appears in converters, amplifiers and sensors. It matters when accurate low-level signals or fine analogue adjustments are needed.

ppm

ppm means parts per million, a common way to express very small gas concentrations in air. For CO₂ sensors, the ppm range tells you what levels the sensor can measure, such as normal indoor air through to poorly ventilated spaces.

programmable gain

An adjustable amplification setting inside the ADC that makes small input signals larger before they are measured. It matters because choosing the right gain helps use more of the ADC’s range without overloading the input.

Programmable gain amplifier

A built-in amplifier whose gain can be changed in software to make small input signals easier to measure. This matters because choosing the right gain can improve detail for small sensors, but too much gain can make the input range too small.

RTD

An RTD, or resistance temperature detector, is a temperature sensor whose resistance changes in a predictable way as it heats or cools, giving accurate and stable readings (PT100 and PT1000 are common types). When a product lists an RTD it indicates precise temperature sensing, which also helps applications such as conductivity probes correct their readings for temperature.

SPS

SPS means samples per second, the number of measurements an analogue-to-digital converter takes each second. A higher SPS gives faster updates, while on many converters a lower sample rate allows higher-resolution or lower-noise readings.

voltage reference

A voltage reference is a stable, accurate voltage that a converter uses as its comparison point: an ADC measures its inputs relative to it, while a DAC scales its output to it. A more stable reference gives more consistent results, which matters most in precision sensing and instrumentation.