Other input devices

	Light PenIt is a light sensitive stylus attached to a video terminal to draw pictures or to select menu options.
	Touch ScreenThis device allow interacting with the computer without any intermediate device. You may see it at as KIOSKS installed in various public places
	Graphics TabletThis device is used to enter data using a stylus. Most commonly it is used to enter digital signatures
	Joystick It is an input device consisting of a stick that pivots on a base and translates its angle or direction as data. Joysticks are often used to control inputs in video games
	MicrophoneIt is used to input audio data into the computer. They are mainly used for sound recording.
	O C R (Optical Character Reader)It is used to convert images of text into machine editable text. It is widely used to convert books and documents into electronic files, to computerize a record-keeping system in an office, or to publish the text on a website.
	ScannerIt is a device that optically scans images, printed text or an object and converts it to a digital image.
	Smart card readerIt is used to access the microprocessor of a smart card. There are two broad categories of smart cards - Memory cards and microprocessor cards. Memory cards contain only non-volatile memory storage components, and some specific security logic. Microprocessor cards contain volatile memory and microprocessor components. The card is made of plastic, generally PVC. Smart cards are used in large companies and organizations for strong security authentication.
	Bar Code Reader This device read the bar code asinput data. It consists of a light source, a lens and a light sensor which translates optical impulses into electrical signals. Also it contains decoder circuitry which analyzes the barcode's image data and sends the barcode's content to the scanner's output port.
	Biometric Sensors It is used to recognize individuals based on physical or behavioral traits. Biometric sensor is used to mark attendance of employees/students in organizations/institutions. It is also popular as a security device to provide restricted entry for secured areas.
	Web CameraThis captures video as data for computer with reasonably good quality. It is commonly used for Web Chats.

Figure 2.4Other Input Devices

Central Processing Unit It is responsible for processing the data and instruction.

Figure 2.5 CPU

This unit can be divided into three sections:

· Control Unit

· Arithmetic and Logical Unit (ALU)

Control Unit

This unit coordinates various operations of the computer like,

v It directs the sequence of operations

v It interprets the instructions of a program in storage unit and produces signals to execute the instructions

v It directs the flow of data and instructions in the computer system

Date: 2015-12-17; view: 784