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Basic things to know about mobile phones

On this page we discuss everything you need to know about mobile phones like: how mobile phone screens are measured, what makes mobile phone screens look very sharp and clear, fixed battery or changeable battery, internal memory or external memory, LCD IPS screen or Super AMOLED display screen, etc. These are some of the basic things you should know about a mobile phone before buying one.

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Most important mobile phone features, things to know before buying a mobile phone

These are a list of mobile phone topics covered. Clicking on any item on this list takes you directly down to that section on this page which is a bit long.

Mobile phone screen size measurement

The mobile phone screen size measurement can be given as an inch size or as a pixel size. For example a smartphone screen size can be 6 inch with pixel size of 720×1080 pixels. We will explain what smartphone screen size in inches mean and what the smart phone size in pixels mean

Mobile phone screen size inches

mobile phone screen size is measured  diagonally

Mobile phone screen size in inches is the standard measurement of a phone’s screen size. Many countries following the metric system, like Europe and India, mobile phone screen sizes are also specified in centimeters. To convert inches into Centimeters multiply the inch value by 2.54 (1 inch=2.54 cms or centimeters). To make screen size in inches from centimeters, divide by 2.54.

It should be remembered that phone screen sizes are always measured diagonally. The image of a smart phone screen here shows the mobile phone screen dimensions in centimeters and inches measured diagonally from the top or bottom corner to the opposite corner at the bottom or top of the screen

The screen size of the mobile phone image here, it is marked as 10.2 cms or 4 inches, the measurement from the bottom left corner to the top right corner. This is how the screen size of a mobile phone is measured.

Mobile phone screen size in pixels

The smart phone screen is made up of thousands of tiny dots called pixels. Each of these tiny pixels can have a different colour controlled by the phones software. It is these different coloured pixels that make the picture on a phone screen. The small squares, in a mosquito-net like pattern in the picture here, are the pixels.

Pixels appear as small squares within the picture

A ‘Pixel” therefore is the smallest element which makes the picture on a screen and ‘Pixel’ is a short form of ‘Picture Element’. The more the number of pixels to make a mobile phone picture or writing, the sharper it becomes and makes the mobile phone screen more easily readable.

The screen pixel size of mobile phones is the number of pixels in the x-axis by the number of pixels in the y-axis. In the picture above of the mobile phone screen, the screen size in pixels is 720×1080.

The number of pixels along the ‘X’ axis or horizontally is shown as 720 pixels and along the ‘Y’ axis or height is shown as 1080 pixels. This is the orientation of the ‘X’ and ‘Y’ axis when the phone is held vertically. When the phone is viewed held horizontally the wider width of phone screen becomes the X-axis and the shorter height of screen becomes the Y-axis, and the phone pixel size should read as 1080×720.

What is the resolution of a smartphone

The resolution of a mobile phone can simply be explained as the pixel density of a phone screen. So mobile phone screen resolution is a measure of how many pixels there are in a unit area, usually in a square inch. Thus smartphone screen resolution means ‘how many Pixels per square inch’ and is usually called ‘Pixels Per Inch’ or PPi. So a mobile phone with a higher PPi will be sharper and will have better readability on the mobile phone screen.

Best screen resolution for smartphone

The best screen resolution for smartphone is about 300 pixels per inch or 300 PPi. Going to a higher value than 400 PPi for phone screens is not that beneficial since there is a maximum PPi above which the human eye cannot make out the difference that well. No doubt, higher phone screen resolutions than 400 PPI do appear a little sharper in some cases, but it is not that much.

How to calculate PPI of a phone screen

The PPi of a smart phone screen can easily be calculated if you know the phone screen size and the phone pixel resolution by using the Pythagoras mathematical formula as shown in in the image here.

pixel density calculator or cell phone screen PPi calculator shows how to calculate PPi of a phone screen

The image shows a 4 inch diagonal phone screen with screen resolution of 720×1080 pixels. This is how the width and height of the screen is worked out as follows:

We assign the value ‘h’ to the height and ‘w’ to be the width of the phone screen. The ratio of the height to width is 1080:720, and therefore the height will be 1.5w (1080/720=1.5). As shown in the calculation in the image, using the 4 inch diagonal screen size of the phone, we get the dimensions of the sides of the phone screen as width=2.63 inches and height as 3.945 inches. From this result the PPI of the phone is calculated as follows:

To find the PPi or pixels per inch of the phone screen, we have to divide the total number of pixels by the total area of the phone screen. Thus we must multiply 1080×720 and the result to be divided by the total area by multiplying 2.63×3.945 (the width and height of the phone screen we calculated above). The result will be 273.764 which will be rounded off by phone manufacturers to 275 PPi. Please note that instead of going to the trouble of multiplying to get total pixels and total area, it is easier to divide for example 1080 by the height 3.945 to get the same result. So just divide the pixel value of a side of a phone screen by the same side length in inches as shown in our image here.

Different types of mobile phone screens

Two types of mobile phone screens, the LCD (Liquid Crystal Display) and AMOLED (active-matrix organic light-emitting diode) are the topmost mobile phone screens available today. The iPhone range of phones and Sony mobile phones have LCD type screens and Samsung smart phones have AMOLED screens which they call Super AMOLED screens.

In LCD and AMOLED mobile phone screens there are variations like IPS LCD screens and Super AMOLED screens. We present here a table comparing IPS LCD and Super AMOLED mobile phone screens with their advantages and disadvantages:

ParameterSuper AMOLEDIPS LCD
Picture QualitySuper AMOLED mobile phones have better color, brightness, viewing angle and quick response time to fast moving action scenesIPS LCD screens also have very good picture quality and only advanced instruments can differentiate between the picture quality of latest LCD and AMOLED mobile phone screens
Picture BrightnessSuper AMOLED screens produces is self lighting, meaning the pixels glow on their own without any back light. So the brightness is very good for indoors, but outdoors in the sunshine it is difficult to see an AMOLED phone screen clearlyIPS LCD works with a backlight and the backlight brightness can be adjusted according to the ambient light. LCD screens are very good indoors and is quite legible outdoors even in direct sunlight.
Thickness of PhoneAMOLED screen mobile phones can be made extremely thin, since the AMOLED screen requires no backlight.Due to the requirement of a backlight, LCD screen mobile phone tend to be slightly thicker than the AMOLED screen mobile phones

Best mobile phone camera megapixels

The common belief is that a phone camera with the higher MP (Megapixel) resolution is the better phone camera. This is not true at all, we explain why

A phone camera with 8MP may sometimes take better pictures than a camera with 20MP. When comparing phone cameras, the things to look for in a phone camera are the size of the sensor and the size of each pixel in the camera sensor. These camera sensor size is more important for a phone camera’s picture taking ability.

The megapixel count or MP of a camera is more important when you need to take large prints of a phone picture. On a TV or computer monitor, a cell phone picture taken with a 5MP camera will look just the same as one taken with a 20MP camera. The reasons for this are explained below.

How important is phone camera megapixels

Just by having more MP does not mean a better phone camera. Phone camera pictures are normally viewed on TVs, computer monitors, Tablets like iPads or on mobile phone screens. HDTV picture with 1920×1080 pixels results in a HDTV picture of 2 million plus pixels or 2 Mega Pixels. The highest resolution TVs available in the market today is the 4K Ultra HDTV with 3840×2160 pixels, which if you multiply 3840×2160 gives a total of 8,294,400 pixels which is just a little over 8 megapixels.

A full HD TV has 1920×1080 pixels which gives just 2,073,600 pixels or 2 Megapixels. So the high megapixel mobile phone camera pictures do not fit into a TV or a computer monitor and has to be compressed to show on a TV. Thus a mobile phone camera picture taken with a 5MP camera will look just the same as one taken with a 20MP camera on a full HD TV but may look a little better on a 4K UHD TV. Again a 8MP mobile phone camera picture and a 20MP picture will look the same on a 4K UHD TV since the maximum resolution of a 4K UHD TV is just 8 MP.

If on the other hand, if you need to print your mobile phone camera pictures, then a high megapixel camera picture will beat a low MP picture. Another big advantage of having a high MP phone camera is that you can zoom the mobile cell images without too much loss of quality and this could be very useful when taking group photos, etc.

Mobile phone Memory explained

mobile phones have mainly two types memory called RAM (Random Access Memory) and ROM (Read Only Memory). The use of RAM in mobile phone speeds up the functioning of all mobile phones. How much RAM do I need for my phone? The short and simple answer is get as much as you can, because the more the RAM the faster the phone applications will execute. 2 GB of RAM will be fine for most applications, but if you do a lot of gaming then try to get the maximum possible, because to have fast responsive gaming experience you need a lot of RAM.

RAM or ‘Random Access Memory’ in a mobile phone is a memory that is temporary, but is quickly accessible to the phone’s processor. The RAM is made up of millions of capacitors each capable of holding one ‘bit’ of information. That means in a RAM of 1 GB there should be at least 1,000,000,000 capacitors since a Giga byte = 1000 Mega bytes where each Mega byte is equal to a million bytes – in short a Giga byte or GB is a billion bytes.

The Capacitors in the RAM lose its charge as soon as it is powered off, so all of the Memory in a RAM can be removed and new memory loaded in the RAM in a fraction of a millisecond just by powering ‘off’ and ‘on’. Thus the memory of a RAM is very volatile and dynamic, and so RAM is referred to as having a ‘Volatile Memory’ and being dynamic, RAM is commonly called as ‘Dynamic Random Access Memory’ or ‘DRAM’.

The Read Only Memory (ROM) in mobile phones store the operating system of the phones like the Android and iOS software. Even though we call it a Read Only Memory: ROM it can be rewritten when the OS is updated. The reason why it is still called a ‘Read Only” even though it can be rewritten is because only a system update can rewrite into those chips and the user cannot rewrite a ROM chip. These ROM chips for storage of the phone OS are usually only about 512 MB.

Mobile phone internal Vs external memory

The main difference between a mobile phone internal memory and external memory is that the phone internal memory is very fast in saving and retrieving info when compared to the external SD card memory. The external memory cards are usually slower to read and write than an internal memory chip. The fastest micro SD card available is the Class 10 micro SD card and is only able to write at a speed of 10 MB/second.

The external SD card memory operates much slower than the phone’s internal memory, so it is always best to have your apps in the phones internal memory. Also while taking photos and videos, it is better to use the phones internal memory and as soon as possible move or transfer the photos and Videos to the external microSD card. This way the camera performs better, and you can free up the internal memory whenever you get a chance.

Mobile phone removable vs non removable battery

Both removable and non removable mobile phone battery have their advantages and disadvantages. We will discuss the advantages and disadvantages of having a removable or a non removable battery in mobile phones

The main advantage of having non removable batteries is that the phone can be built much thinner and more robust. The internals of the phone are sealed and protected from moisture and dust. There is no danger of the phone back covers and batteries coming out when the phone is accidentally dropped. Problems with mobile phone non-removable battery are one, when the mobile cell phone freezes up or hangs and you cannot remove the battery to reboot the phone and two, in the event the battery needs to be replaced, it can only be done at the service centre of the phone manufacturer.

The main advantage of having smartphones with replaceable battery are that in case the phone hangs-up or freezes-up, you can simply remove and reinsert the battery to reboot the phone. The second major advantage of having a removable battery was that you could have a fully charged spare battery, which could be exchanged for the dead battery in the phone and have a ful charged phone which could work for hours.

Both of these advantages of having a removable battery in a mobile phone is not there any more. Latest smartphones have keyboard shortcut buttons to reboot a hanged or frozen smartphone operating system. The advantage of being able to replace dead batteries with a fully charged batteries have been neutralised with modern day USB Power Banks which can recharge a dead or low battery mobile phone on the run.

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Advantage of Online buying of Home Appliances

Whatever Home Appliance you plan to buy, it is best to first do an online research about all available types and models on the leading online retailers in India, namely Amazon, Flipkart and Snapdeal. The advantage of first doing an online research about products you plan to buy is that you get to see all the available models of the product and you get to compare prices online. After this you can go around to the showrooms and do window shopping.

You should then decide to buy from the cheapest and most reliable source. When buying online, you can be sure that you will not get fake products and you are assured of after sales service. This is because the giant on-line retailers arrange for delivery to your house directly through the manufacturers of the product. Due to the high volume of business from the big online retailers, all manufacturers will make sure that any delivery on behalf of the big online retailers are of the best quality and that after sales service is provided on a priority basis.

If ever you have any problems, then you can go back to these online retailers and complain. All of these big online sellers have a reputation to keep and they always make sure that all complaints are promptly solved.

Advantage of buying AC, Fridge, Washing Machine, etc. online

Buying online fridges, washing machines, dishwashers and other major kitchen appliances is now the better option in India, just like it is in the USA and other advanced countries. There are several advantages of buying online. First of all, you get unbeatable bargain prices. Secondly, you get new and genuine products. Other benefits include no interest EMI payments, able to return the product for a full refund if not satisfied, etc.

Just to give you an example, below are some of the benefits Amazon India, the leading global online retailer, offered in India during their last sale. The same deals are not always available, but it is a good idea to check this link to the special offers page on India website.

Link to deals