A data acquisition system (DAS or DAQ) is a group of sensors, hardware components, and software programs that all work together for the purpose of collecting physical or real world signals. The DAS may be as simple as a personal computer with data acquisition hardware peripherals and software. If the DAS is as a stand-alone system with dedicated software that is only capable of performing data acquisition, it may be referred to as a data logger.

The first stage of any DAS is the sensors or transducers. These devices convert some type of real world physical signal  (such as sound, pressure, ambient temperature, fluid flow rate, etc.) into an electrical signal. Usually, the DAS will have some signal conditioning circuitry such as analog filtering in the signal chain. This conditioning prepares the signal for data conversion from analog to digital through the analog-digital converter (ADC). This converted data is sent to the main processing unit such as a computer via a port or slot. The main processing unit manipulates the data through the use of dedicated hardware and software.

Although the DAS may run its custom software, there are more widely available PC software packages, which can be used for controlling the DAS's hardware. LabView and MATLAB are two examples. It is also possible to directly control the DAS hardware via C or another low-level programming language.