Scroll wheel

A jog dial is a control on the electronic equipment in the form of a rotatable wheel with a finger, which is used for adjusting a value or an ergonomic position. Since the late 1990s, it is particularly as a scroll wheel ( scroll wheel ) widely used in computer mice, where it is used to control scrolling in graphical user interface ( " scroll " ) or the magnification ( " zooming ").

History and distribution

As part of Jog / Shuttle Jog Dials were to be found as early as the 1980s on VCRs and laser disc players from different manufacturers.

The first equipped with a scroll wheel mouse computer was sold from 1996 Microsoft IntelliMouse. It contained a wheel to control the vertical scrolling between the left and right mouse buttons, which could be also press and thus be used as a third mouse button. Shortly thereafter began other hardware manufacturers to produce compatible mice; the end of the 1990s, the scroll wheel was established on PC mice. Chance also appeared mice on the market, which were equipped with a second wheel for horizontal scrolling ( about 2000 ), or instead of the scroll wheel had a scroll ball that is physically similar to a trackball and also two-dimensional scrolling allowed ( 2002).

As in laptops often instead of a mouse, for example, a built-in touch pad is used, a scroll is incorporated into some of these machines. However, modern touchpads can be used by moving the finger on the right or bottom edge, or by two-finger swipe to scroll too, so an additional scroll wheel is no longer necessary.

Since the early 2000s Jog Dial also be installed in many portable devices such as PDAs, mobile phones or MP3 players, where they are also used mainly for scrolling in lists.

Installation and use

Unlike based potentiometers knobs, such as the common volume controls on radios, located jog dial can rotate without in both directions; the set value is not determined by the absolute position of the wheel, but can be relatively changed by rotation. This allows large or variable value ranges are covered. The purpose component used is a rotary encoder, which is used among others for measurements on machine tools.

A similar control is the shuttle dial, but with this, the speed is determined by the position of the wheel with which the value is automatically increased or decreased.

Often jog dials are provided with a grid, so that let you feel the individual change steps during rotation.

For the installation of a jog dial there are generally two options:

• The wheel is mounted on the flat surface of the device. Jog dial of this kind are, for example, on many DVD video recorders or iPods of the first generation (2001) and allow the user to rotate the wheel as long as desired without discontinuation of the finger.
• Only part of the edge of the wheel is accessible. This is less space on the device surface is required, but the user can only turn the wheel without lifting the finger a short distance. This construction is used for scroll wheels in computer mice, and PDAs.

Mouse wheel in different computer systems

Mice with scroll wheels were initially intended for PCs and supported under Microsoft Windows.

In contrast, mice of Unix workstations traditionally have three right mouse buttons and scroll wheel no; Sun workstations are shipped with mice without wheel, for example, to this day. About running on PC hardware Unix operating systems ( Linux in particular ) the scroll wheel but has also been introduced in the Unix world and can be used under Unix GUIs like Gnome or KDE for the scrolling. The function of the middle mouse button that was traditionally required on Unix -like systems, is guaranteed more or less well by today's conventional depressible scroll wheel.

Although Apple had received years before the IntelliMouse a patent on a wheel in a mouse, Macintosh users had to make do for a long time without mouse wheel. Only since August 2005, Apple Mighty Mouse with a mouse with a scroll ball on.

Support in graphical user interfaces

Which action turning a mouse wheel actually triggers is determined by the application program or the underlying operating system or GUI toolkit. It is usual in addition to the scrolling to a certain number of rows and the adjustment of graphically simulated sliders or numeric input fields. Moreover, it is often for zooming application.

Since several controllable by the scroll wheel windows and widgets can be visible on the screen at the same time, the action triggered by the position of the cursor and the cursor, and determined by which window is active.

In many cases, by pressing modifier keys, the effect can be changed, such as Google Chrome, Firefox or Internet Explorer can be used in the web browser Opera, the zoom level is changed while holding down the Control key with the scroll wheel - hence the too common term " mouse wheel " is actually more general and correct than " scroll wheel ".

• Control element
• Input Device