There are two exact definitions of educational technology, which are quoted in various documents: one is the Dictionary of Education 1990 published by Shanghai Education Publishing House, which defines educational technology as "the sum of all technical means adopted by human beings in educational activities, including materialized technology and intelligent technology." The other is the definition issued by the American Society for Educational Communication and Technology (AECT) in 1994: Educational technology is a research and ethical practice that promotes learning and improves performance by creating, using and managing appropriate technological processes and resources. As can be seen from the definition, on the one hand, modern educational technology emphasizes the application of modern educational technology such as computer, multimedia, network technology, artificial intelligence and virtual reality, on the other hand, modern educational technology does not ignore or resist the application of traditional media technology. Summarizing these two authoritative definitions, we can understand the connotation of educational technology from three aspects:

1. Educational technology is a variety of materialized means used in the educational process. From the most basic blackboard, chalk, text teaching materials, teaching AIDS, projectors, slide projectors, televisions, wired and wireless sound reinforcement systems and video display stands to multimedia computers, CAW closed-circuit television teaching network systems, computer two-way transmission interactive network systems, etc. Are all hardware components of educational technology.

2. Educational technology is a carefully selected and reasonably organized learning textbook. These learning materials should not only meet the needs of society and students' personal learning, but also conform to the cognitive laws and be suitable for students' learning. This is a software component of educational technology.

3. Educational technology is also a method to design, implement and evaluate the teaching process. Such as Comenius' intuitive teaching method, Herbart's four-stage teaching method and the heuristic teaching method advocated by Confucius, an ancient educator in China. This is also an integral part of educational technology.

Therefore, the system composed of hardware, software and teaching methods is a complete concept of educational technology. In other words, educational technology is a system composed of teaching hardware, software and teaching methods.