根据概念创建者美国国家仪器公司（National Instruments）的定义，虚拟仪器（英语：Virtual instrumentation）技术就是利用高性能的模块化硬件，结合高效灵活的软件来完成各种测试、测量和自动化的应用。灵活高效的软件能帮助您创建完全自定义的用户界面，模块化的硬件能方便地提供全方位的系统集成，标准的软硬件平台能满足对同步和定时应用的需求。只有同时拥有高效的软件、模块化I/O硬件和用于集成的软硬件平台这三大组成部分，才能充分发挥虚拟仪器技术性能高、扩展性强、开发时间少，以及出色 的集成这四大优势。

Virtual instrumentation is the use of customizable software and modular measurement hardware to create user-defined measurement systems, called virtual instruments.

Traditional hardware instrumentation systems are made up of pre-defined hardware components, such as digital multimeters and oscilloscopes that are completely specific to their stimulus, analysis, or measurement function. Because of their hard-coded function, these systems are more limited in their versatility than virtual instrumentation systems. The primary difference between hardware instrumentation and virtual instrumentation is that software is used to replace a large amount of hardware. The software enables complex and expensive hardware to be replaced by already purchased computer hardware; e. g. analog-to-digital converter can act as a hardware complement of a virtual oscilloscope, a potentiostat enables frequency response acquisition and analysis in electrochemical impedance spectroscopy with virtual instrumentation.