Information Technology Reference
In-Depth Information
and the sensor measures it, and those measurements are reported back
to the computer to tell the pointer how to move. Mechanical mice need
frequent cleaning; optical mice are maintenance-free and have virtually
replaced the mechanical type.
© iStockphoto.com/luismmolina
Figure.3 3
The underside of an optical mouse contains a
red light and a sensor that measures its reflection from
the surface the mouse is used on.
Like a keyboard, a mouse can have a wire (cord) connecting it to the
computer, or it can be wireless. A
wireless mouse
communicates with
a
transceiver
connected to a USB port to exchange data with the com-
puter, or uses a technology called Bluetooth to communicate via radio
waves. A wireless mouse requires a battery, whereas a wired mouse draws
the small amount of power it needs from the computer via its cord.
wireless mouse
A mouse that communicates
wirelessly with a transceiver connected to the
computer, so it does not need a cord.
transceiver
A unit that provides the wireless
transmission for a cordless device like keyboard or
mouse, usually plugged into a USB port.
Other pointing devices are also available. For example, a
trackball
is a
stationary device with a ball on top (or on the side) that you roll with
your fingers. See Figure 3.4. A trackball requires less space on a desk to
operate and some people find it more comfortable to use than a mouse.
Many notebook computers have a built-in
touchpad
, which is a small
rectangular touch-sensitive pad with buttons below it. See Figure 3.5.
You can drag your finger on the pad to move the onscreen pointer, and
press the buttons to click.
trackball
A pointing device in which the user
moves the pointer by rolling a ball with his or her
fingers.
touchpad
A pointing device consisting of a
touch-sensitive pad on which the user drags a
finger to move the pointer.
© iStockphoto.com/epixx
Figure.3 4
A trackball is stationary; the user moves the ball
with his or her fingers.
