Being one the older members of this forum, I remember when the concept of "appropriate technology" was something of a fad. It seems to me in recent years that fad has faded and there is little discussion of the topic in comparison with its peak in popularity. So I googled the topic and came upon the article the link to which I have provided above. Although I have cited extracts below, I encourage the reader to read the entire article. It is not that long and I am am hopeful that it will help to introduce the topic to this forum.
E.F. Schumacher published Small is Beautiful: Economics as if People Mattered, and the emphasis changed to what was dubbed "appropriate technology"...The appropriate technology movement died peacefully in its sleep ten years ago...it inspired politicians as different as Pat Brown in California and Jawarhal Nehru in India...The appropriate technology movement died because it was led by well-intentional tinkerers instead of hard-nosed entrepreneurs designing the market. In her book Dead Aid, ...Dambesa Moyo...notes that aid is counterproductive. She quotes a World Bank study that found 85% of aid is misused. She argues that large aid inflows tend to reduce a government's accountability to its citizens. So there appears to be two opposing views: the bottom-up approach, in which one only responds to what people want, and the top-down approach, where you give people what you think they need. But there is an intermediate approach, in which there are some things that should be given because they are basic human needs, while other things the recipients should be allowed to choose for themselves...So it would seem that the old style appropriate technology project has essentially died, but a new kind of project with better market orientation, but still very much appropriate, has emerged from the ashes.
Here is a link to the Wikipedia write-up on the subject. It is a bit longer than the original article I cited, but may be helpful in understanding the concept.