Passive-matrix is an LCD technology that uses a grid of vertical and horizontal wires to display an image on the screen. Each pixel is controlled by an intersection of two wires in the grid. By altering the electrical charge at a given intersection, the color and brightness of the corresponding pixel can be changed.
While passive-matrix displays are relatively simple and inexpensive to produce, they have a few drawbacks. Since the charge of two wires (both vertical and horizontal) must be altered in order to change a single pixel, the response time of passive-matrix displays is relatively slow. This means fast movement on a passive-matrix display may appear blurry or faded, since the electrical charges cannot keep up with the motion. On some passive-matrix displays, you may experience "ghosting" if you move the cursor quickly across the screen.
Since passive-matrix monitors do not display fast motion well, most modern flat screen displays use active-matrix technology. Instead of managing pixels through intersections of wires, active-matrix displays control each pixel using individual capacitors. This allows pixels to change brightness and color states much more rapidly. While most of today's computer monitors and flat screen televisions have active-matrix screens, passive-matrix displays are still used in some smaller devices, since they are less expensive to produce.