Keyboard

Figure 1-18.—Microcomputer’s system unit with cover removed. Figure 1-19.—Monitor controls, switches and indicators. work in conjunction with the microprocessor located on the system or motherboard itself. These boards provide the flexibility to add a variety of capabilities to a basic system. Certain boards are required, such as the system board that contains the main microprocessor(s). Others you might add to control a light pen or a mouse device or to handle a communications interface. MONITOR The monitor, also known as the screen, display, display device and cathode-ray tube (CRT), is the principal link between you and the microcomputer (fig. 1-19). Its sole purpose is to allow the micro- computer to communicate its actions to you, the user, so that you can act upon those actions to accomplish whatever job you are doing. Monitors can display information in either monochrome or color, depending on their design. Monochrome displays produce output images using a single foreground color, such as black, and a single background color, such as white. This provides you with black text on a white background. Monochrome displays also come in amber and green. Amber and green are considered more pleasing and less stressful to the eyes. Most color monitors are of the red-green-blue (RGB) type. Depending upon the sophistication of the display device and the amount of RAM (random access memory) available with the microcomputer, you may be able to display from eight to 16,000,000 colors. Brightness and contrast adjustment dials are usually located on the front of the monitor. Some monitors come with a sizing feature that allows you to increase or decrease the physical size (the height and width) of the displayed information. Monochrome monitors may be equipped with an amber/normal/green dial. With it, you may select any one of the three positions to give you that specific color. KEYBOARD Of all the components that make up a micro- computer, you will become most familiar with the keyboard (fig. 1-20). It will probably be your main means for inputting programs and data on micro- computers. Keyboards come in many shapes and sizes, have different numbers and arrangements of keys, differ in respect to touch and have special keys to allow you to communicate specific software commands. Most manufacturers have designed their keyboards as Figure 1-20.—Microcomputer keyboard. 1-51