What is an AI chip? Everything you need to know

Many of the smart/IoT devices you'll purchase are powered by some form of Artificial Intelligence (AI)--be it voice assistants, facial recognition cameras, or even your PC. These don't work via magic, however, and need something to power all of the data-processing they do. For some devices that could be done in the cloud, by vast datacentres. Other devices will do all their processing on the devices themselves, through an AI chip. But what is an AI chip?