Smart phone

The evolution in hardware, software, and communication made the ground for evolving mobile phones from just portable phones to smartphones. These days, purchasing a mobile is a little bit confusing because of the number of brands, models, technologies, and requirements.
What are the things that make a mobile phones into smartphones?
Basically every mobile phone has a CPU, an input/output mechanism, display, speakers, and battery. What makes the mobile phone dearer to people or unavoidable in daily life? Everybody uses a smart phone, and they use it to accomplish certain purposes, most commonly communication and file sharing. For some users, purposes are more than the common ones, and some only need a very little of what is available. So to fulfill the requirements, a variety of models with low-end to high-end configurations are available. Choosing a suitable device is not difficult, but quality-wise, it is a little complicated. Knowing something about it certainly helps resolve confusions.

A smartphone is a complicated device, but it is designed in such a way that for a user it is a very simple thing. It has lots of complicated hardware, software, and sensors combined to work together for various purposes and circumstances. For users something matters the most; for example, some users seek a phone with a good camera, some require a good display, good battery life, good looks, etc. The great thing is that there are lots of choices available. 

So, what are the things you need to know about smartphones? Here is some little description about.
A smartphone has all the things a computer (mostly laptops) has, such as a processor, storage, output unit, input unit, and additional sensor. Let’s begin with the brain.

CPU:

A Central Processing Unit (CPU), the brain, or Processor, which is an important component of any smartphone, performs all operations and controls. In Smartphones, the central processing unit (CPU) is a single microchip system with System-on-chip (SoC) technology, which means that the microchip contains all the things a system or device requires. This microchip is embedded with CPU, GPU, AI processor, connectivity, RAM, Camera, audio/video, and display. In a simple statement, a high-end processor will support and offer the latest features available with these components.

By checking the clock speed and number of cores, one can gain a glimpse into the power of a processor. Clock speed indicates how fast a processor is or how fast it performs tasks. Typically, as mentioned for gigahertz (GHz), higher GHz numbers result in better performance. The number of cores determines how efficient a processor is. Processors come with a different number of cores such as single-core, dual-core (2 cores), Quad-core (4 cores), and octa-core (8 cores). More cores mean it implements multiple tasks/tasks efficiently with no lag, but it does not mean speeding up processes. These clock speeds and cores always impact the power consumption, performance, and efficiency of the smartphone. Apple, Huawei, MediaTek, Samsung Exynos, and Snapdragon are the major and popular mobile processor manufacturers these days. Intel and Nvidia have also made contributions to smartphone CPUs.

RAM:

Random Access Memory (RAM) is a fast and volatile memory that loads applications from slow, non-volatile, permanent storage on the central processing unit (CPU). Smartphones are capable of performing more than one task simultaneously at a time. All tasks are stored in RAM and serve it very quickly upon request. For example, a user can open any app without closing them. Thus, if a user opens apps one after another, up to five apps may be currently in use, and the remaining four apps are stored in RAM ready to run on user command. If the user opens another app again, the current app returns to RAM with the rest of the apps. Thus, when the user opens an app that was opened earlier and stored in RAM, the RAM serves the app from its storage to the processor and stores the current app.

Currently, smartphones are equipped with RAM ranging from 1 GB to 8 GB. The minimum RAM requirement for a current smartphone is 2 GB, and the maximum is 4 GB. The capacity of the internal storage may affect the RAM performance, which results in system performance

Display:

Earlier, displays in a phone are just output units to show information like who is calling, who called, contact information, and reading messages. But things are different in a smartphone; it acts as an output unit at the same time as an input unit too. The mobile responds to its user as he/she touches the display, performing activities such as making a call, typing messages, opening an application, etc. performed by touching the display. Touch screen sensitivity is the technology behind this. The displays used in smartphones are remarkable. Every Smartphone available in the market is equipped with a minimum HD display and touch sensitivity. There are two main types of display used in mobile phones: liquid crystal display (LCD) and the other is OLED (Organic Light Emitting Diode). The mobile device comes with an LCD or TFT LCD screen. Many improvements have been applied to LCD displays for a better viewing experience, such as in-plane switching (IPS), which helps the user to view at a wider angle with better color reproduction. The latest OLEDs, AMOLED (Active Matrix OLED), and superAMOLED (sAMOLED), are advancements over LCDs and deliver sharper and brighter images and consume less power

Retina displays are another type of display technology that gives super sharp and high-quality images. The high-density pixel packing gives a natural appearance to text and images in Retina display. Pixel density is so high that it is impossible for the human eye to detect individual pixels

Current trends in smartphone are thin body around the display known as bezelless (less/no frame around display) body with body to display ratio, in which the display takes the maximum area of the surface to give the user a big viewing experience. The display is the main component of a mobile phone that people are most attracted to. Curved and foldable displays are the latest existing and upcoming features.

Battery:

Every electronic device needs a power source to work. For the mobile devices, this is very critical. The only solution available is to use batteries or cells. There are two types of batteries used in a smartphone: (1) Lithium Polymer (Li-Po) and (2) Lithium Ion (Li-ION). Nowadays almost all smartphones come with a Li-Po battery, but earlier it was Li-ion. Li-Po batteries are a little costlier than Li-ion, and both have their advantages and disadvantages. Li-ion has more energy density and is cheaper. Li-Po has a shorter charging duration, is lightweight, retains charging capacity longer, and above all, concerning safety, Li-Po is the right choice. Smartphones come with removable and non-removable battery types. Both types have their merits and demerits. 
Merits: Mobile phones with removable batteries have options like replaceable batteries, hard resetting on hanging, and low cost. Mobile phones with non-removable batteries have a slim, light, and sturdy design that is water and dustproof. 

Demerits:  On interchanging the merits with each other, both types have opposite effects on merits. Advises and opinions from different people are these, non-removable battery phones always have good batteries, help people to avoid using fake batteries in case replacement, easy insertion of SIM and storage cards, and manufacturers have to use high-quality materials. Also helps recover phones because the security system cannot disable them.  Removable battery phones allow you to have a spare battery, are easily replaceable without visiting authorized service centers, have better resale value, and require less heating. 

ROM:

Read Only Memory (ROM) is the storage location of Smartphone which holds OS, various apps, media files. This storage is usually known as internal storage. Nowadays Smartphone are comes with minimum of 8 GB- 32 GB internal storage which can be extended to maximum, upto factory specific capacity, using storage cards through dedicated card slots. Some manufacturers equipped their product with huge internal storage ranging from 64 GB to 256 GB.
Typically smartphone uses embedded Multi Media Controller (eMMC) to store information. The latest flash storage technology called Universal Flash Storage (UFS) is being equipped in latest flagship devices. UFS comes with the abilities of both eMMC and SSD storage. It is much faster than available storage out there.
The choice of memory is depend on use. For user who capture videos and photos must need good storage phone (16 GB is fine 32 GB is sufficient). For entertainment such watching movie offline, for high graphic games may require huge storage (32 GB will be do good). Availability of extending storage through memory cards, OTG USB/ Pen drives solves most storage related things. Increased internal storage may decline the performance of the phone if the RAM is not enough. The ratio would be fair for 1 GB RAM for 8GB ROM, 2 GB RAM for 16 GB ROM 3 GB RAM for 32 GB ROM and 4/6 GB for 64 GB. Additional storage may decree the system performance somewhat if the RAM-ROM ratio is not fair.

Camera:

For normal user a mobile phone without camera is unthinkable and unimaginable. The technologies used in digital camera or web camera are followed in mobile camera. There are two types of sensors used in camera Complimentary Metal-Oxide Semi-conductor (CMOS) and Charged Coupled Device (CCD). Almost all phones use CMOS sensor. Most people look for Smartphone with good camera, and would decides the photo quality by checking how much megapixel (MP) the camera has. The real thing is more MP does not mean the camera give you quality picture. Picture quality is depends on sensor quality, lens quality and low-light image capturing ability.
High quality video and photos are easily captured using the camera. The camera features such as zoom, low-light/night, wide angle, potrait mode , Slow-motion, time-lapse. Power of smart phone camera is mainly depend on software and hardware level. The phone with good hardware produce good results. Software is secondary thing which mainly helps in controlling the hardware. User can use the third party application to capture photos/video for their satisfaction.

Connectivity:

The basic connectivity a phone required is done with SIM card provided by a service provider. 2G, 3G, 4G services are the most common network services available for person to person communication through mobile phones. Almost all Service providers updates their networking capabilities with latest to provide best services to customer. The recent announcement about the 5G connectivity is the latest updates. Every updates in the networks, mobiles manufacturers also keep the pace But for smart phone, communication is not merely persons to person it means information/service on the move. For instance user can book a seat in train, flight, cinemas, request latest news, present weather condition, direction to a particular location or place, share location with other person, sharing file. Most of the things mentioned above can be done by just connecting to internet, some of them are with satellite and some with devices near. 3G/4G connectivity or inbuilt WLAN (WIFI) helps user to connect to Internet. With A-GPS, GLONASS, GALILEO, QZSS, BeiDou etc. helps users to communicate with satellite, with USB (OTG) cable connectivity, Infra Red, Bluetooth wireless technology helps transferring file between devices, with hot spot user can use the device as wireless modem. Near Field Communication (NFC) is another connectivity technology enables communication between devices when they're touched together, or brought within a few centimeters of each other.

Sensor:

A phone becomes smart when it can sense and respond accordingly. There are different types of sensors in a smart phone. Each has different jobs and some related to other. Accelerometer, Gyroscope, Magnetometer, Proximity sensor, GPS, Light sensor, Finger print sensor, Pedometer, Barometer, Heart rate sensor, Thermometer, Air humidity sensor and Geiger counter and Touch screen these are sensor a smart phone can have. Most of the smart phone available in the market does not all of these but have most of these. Sensor such as Accelerometer, Gyroscope, Magnetometer | Compass, Proximity sensor, GPS, Light sensor, Finger print sensors are common in all smart phones. Gyroscope sensors enables the auto rotation of screen, capturing 360° Sphere(VR) photos, tilting screen while playing games, Accelerometer sensor used to measure the acceleration forces, it helps to detect the orientation of the phone. This sensor used in smart phone helps to track the steps. So while walking or jogging smart phone track your activity. Augmented reality app this sensor is very important, Magnetometer | Compass sensor take charge when Map application starts, it measures the magnetic field and tells user which direction is north (N), and the data from accelerometer and GPS used by magnetometer and detect the user location on earth. Ambient light sensor and proximity sensor use the light to control/adjust screen brightness. Proximity sensor is a sensor that detects or senses nearby objects without physical contacts. When user gets a call or making call, just before the user placing the phone at ear the screen/display turned off, so as to disable touch sensing. This is the role of proximity sensor in smart phones. The Light sensor is responsible for adjusting the screen brightness according to the surrounding. Fingerprint sensor is a biometric sensor used as security applications. These days all phones are equipped with finger print sensor as a security feature and offer convenience. Global Positioning System (GPS) is sensor which communicates with satellite to detect the location of phone. Some smart phones available in the market are equipped with Thermometer to measure temperature around, barometer to measure atmospheric pressure and altitude, Geiger counter to measure the radiation level. The list goes on

Audio/Video:

The amazing internet and mobile computing technology enabled a seamless entertainment on the move . Watching sports, movies, listening music,NEWS, sharing photos and files, live streaming of audio and video, shopping, etc; are performed on the move. All these are done through Smart phones. Bluetooth enables user to connect her smartphone to external audio devices such headphones/earphones, hi-fi music player. Using auxiliary cable user can connect to external devices. There various formats of audio /video are there. Smartphones have the capabilities to play almost all formats available. A good internal speaker is much satisfaction for user who care about audio quality of phone, a good DAC equipped smartphone gives a great quality sound through good quality headphones/earphones.
With the Internet and advanced networking and communication technology user can have quality audio/video. Virtual Reality (VR), Augmented Reality (AR) makes entertainment into another dimension.

Body: The body and color is the another thing people care about. The material used gives the look, feel and durability for phone. Plastic, metal, ceramic and glass are type body used for smart phones.
Metal type body gives premium look, but, it dissipates heat in and out, chance of radio inference and usual denting bending metals are also happens with it. The wireless charging is difficult with metal type body. But using metal alloys or spacial metal can avoid the problems but cost will rise. For shiny look, most phones comes with glass type body (Corning’s Gorilla Glass mostly) there lot of advantages using glass over metal, most of the drawbacks of metal are solved using glass. Glass body type phones are mostly flat. Usual behavior of glass such as fragility, slippery and frequent cleaning requires. Ceramic is harder than glass or plastic, but, lighter than metal and very costly. Ceramics scratch free comparing with metal, glass and plastic. Most disadvantages of metals and glass also have happens with ceramic body.
Almost every phone is packed with plastic body(Poly carbonate), for durability, price-cutting and to reduce major draw backs of metal, glass, ceramic materials. Poly-carbonate, which has high impact resistance, relatively good temperature resistance, and extreme flexible, is the material used in building mobile body. Poly-carbonate is lightweight, tough and durable material and gives maximum protection against accidental drops.

Reference: History Mobile Cell Phone SoC Display Battery Sensors Sensors AR Audio UFS