There are many different display technologies such as LCD, OLED, EPD, and ECD. They are all based on fundamentally different technologies with various driving requirements. Even so, all of them share some basic ideas of how to drive them. In this article, I will explain some fundamentals in display driving. This is relevant whether you are a professional engineer designing display applications or if you are a hacker exploring seven segment displays for your Arduino projects. If you are just interested, well, this article is for you as well.