A mobile device, also called a handheld computer, is a small computer that you can hold in your hand and use. Handheld computers usually have a flat LCD or OLED screen with either a touchscreen with digital buttons and keyboard or physical buttons and a physical keyboard. Many of these devices can connect to the Internet and to other devices, like car entertainment systems or headsets, through Wi-Fi, Bluetooth, cellular networks, or near field communication (NFC). Most have built-in cameras, the ability to make and receive voice and video phone calls, video games, and the ability to use the Global Positioning System (GPS). A lithium-ion battery is often used to provide power. Mobile devices can run mobile operating systems that let third-party apps be installed and run.
In the late 2000s, bigger tablets came out along with the first smartphones. Most of the time, you use a touch screen to input and output information. Phones, tablets, and personal digital assistants (PDAs) may be able to do a lot of what a laptop or desktop computer can do, and they may also have their own features.  Enterprise digital assistants can do more for businesses, like capturing data with barcode, RFID, and smart card readers all at once.
By 2010, most mobile devices had sensors like accelerometers, magnetometers, and gyroscopes that could tell how the device was moving and how it was oriented. Biometric user authentication, like recognising a face or a fingerprint, can be done on mobile devices.
Apple, Samsung, Huawei, Meizu, Zte, Xiaomi, Sony, Google, HTC, LG, TCL, Motorola Mobility, Nokia, Realme, and Micromax Informatics are some of the biggest phone makers in the world.
4 See also
There are a few ways to look at the mobility of a device:
How big and heavy something is
Whether the device itself or the host to which it is connected is mobile.
What kinds of hosts can it be tied to?
How devices talk to their hosts
When the movement takes place
Many so-called mobile devices are not mobile in the strictest sense. It's the host that moves, so a person who moves carries a smartphone that doesn't move. A robot is an example of a true mobile computing device, which means that the device itself moves. A self-driving car is another example.
There are three main ways that mobile devices can be physically connected to mobile hosts: they can be with the host, mounted on the outside of the host, or built into the host, like a controller built into a host device. Accompanied means that an object is loosely attached to a mobile host. For example, a smartphone can be carried in a bag or pocket, but it is easy to lose.  Because of this, mobile hosts with built-in devices, like a self-driving car, can look bigger than pocket-sized.
Most mobile computing devices are small enough to fit in a pocket and can be held in one hand, but there are other sizes. Mark Weiser, who is known as the "father of ubiquitous computing" or "computing everywhere," talked about devices that are tab-sized, pad-sized, and board-sized. If you change the shape of a mobile device so that it is no longer flat, you can make skin devices and devices that are the size of dust.  Dust is a term for small devices that don't have direct HCI interfaces, like micro electromechanical systems (MEMS). These devices can be anywhere from a few nanometers to a few millimetres in size. Also see Smart dust. Skin: Light-emitting and conductive polymers and organic computer devices are used to make the fabrics that make up the skin. These can be made into more flexible, non-planar display surfaces and products like clothes and curtains, see OLED display. See smart device as well.
Mobile users, apps, and devices don't have to use wireless networks for all network access, and the same goes for wired networks.
The hardware and software of a mobile device are more flexible than other technologies. This is what makes it stand out. Some examples of flexible applications are video chat, browsing the Web, payment systems, NFC, recording audio, and so on.  As more and more people get mobile phones, there will be more and more services that use the cloud.
Smartphones and other hand-held phones
Smartwatches and handheld phones
. Among them are:
Player for digital media
Enterprise digital assistant
Calculator for graphs
Handheld video game system
Handheld PC \sLaptop
Mobile Internet device (MID)
Personal digital assistant (PDA)
Handheld media player
Digital still camera (DSC)
video camera (DVC)
Camera on the front
Personal navigation device (PND)
Computers you can wear
Display worn on the head
Mobile field management can now use handheld devices that are more durable. For example, scanning barcodes, sending and receiving invoices, managing assets, digitising notes, sending and receiving invoices, recording signatures, managing parts, and managing assets
In 2009, improvements to mobile collaboration systems made it possible for people to use handheld devices that combine video, audio, and on-screen drawing to let multiple people meet in real time, no matter where they are.
 Handheld computers come in many shapes and sizes, from smartphones on the low end to handheld PDAs, Ultra-Mobile PCs, and Tablet PCs on the high end (Palm OS, WebOS).
 Users can use IPTV on some mobile devices to watch TV over the Internet. Mobile TV receivers have been around since the 1960s, and mobile phone providers started putting TV on cell phones in the 21st century. 
In the 2010s, mobile devices can sync and share a lot of data, no matter how far apart they are or what they can do. In the medical field, mobile devices are becoming more and more important for getting information about drugs, treatments, and even medical calculations.  Due to the popularity of mobile games, the gambling industry started offering casino games on mobile devices. Other things that could be illegal include sending child pornography through mobile devices, the legal sex industry using mobile apps and hardware to promote its services, and the possibility of using mobile devices to provide services across borders. All of these things need to be regulated. Mobile devices have given the military new ways to train and educate soldiers no matter where they are stationed. 
Here is a list of new technologies
Smart device Mobile interaction Near Field Communication (NFC)
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vte: Largest companies that make mobile devices
vte: Sizes of computers
Mobile operating systems Controlled by: National libraries You can change this on Wikidata Germany
Things that help you get information
Personal digital assistants