Some Basic information about android tablets.(Some information sourced from Wikipedia)
An android tablet is a communication and multimedia device that runs using an android operating system. These tablets are the latest generation of portable computer technology with immense connectivity capabilities and resolution. Like a desktop PC, an android tablet PC is made up of component parts: a Central Processor Unit, (CPU) a Graphics Processing Unit, (GPU) memory chips both Read Only Memory (ROM) and Random Access Memory (RAM), the android operating system, a display screen and a battery. This is of course a much simplified description but it helps us understand what these things are when we are talking about our tablets. It is normal for a tablet to get warm in use as both the battery and the processors generate heat when in use.Memory
The type of memory chips used on an android tablet are often referred to as being DDR.
This stands for double data rate which nowadays has replaced the older SDR chips which were single data rate. Tablet memory is usually divided or partitioned into sections which are then used for different purposes so you may be disappointed to discover that a tablet advertised as having 4Gig memory may only have a fraction of that available for your apps as the rest is taken up by the android system and preinstalled apps necessary to make the tablet work.Display Panels
Tablet PC’s are made with various touch-screen display panels each differing in the way they work, their screen resolution, toughness and their quality. The two types you are most likely to come across are resistive and capacitive in operation.
A resistive touch-screen panel comprises several layers, the most important of which are two thin, transparent electrically-resistive layers separated by a thin space. These layers face each other, with a thin gap between. The top screen or the screen which experiences our touch has a coating on the underside surface of the screen. Just beneath it is a similar resistive layer on top of its substrate. One layer has conductive connections along its sides, the other along top and bottom. A voltage is passed through one layer, and sensed at the other. When an object, such as a fingertip or stylus tip, presses down on the outer surface, the two layers touch to become connected at that point: The panel then behaves as a pair of voltage dividers, one axis at a time. By rapidly switching between each layer, the position of a pressure on the screen can be read.
A capacitive touch-screen panel consists of an insulator such as glass, coated with a transparent conductor such as indium tin oxide (ITO). As the human body is also an electrical conductor, touching the surface of the screen results in a distortion of the screen's electrostatic field, measurable as a change in capacitance. Different technologies may be used to determine the location of the touch. The location is then sent to the controller for processing. Unlike a resistive touch-screen, one cannot use a capacitive touch-screen through most types of electrically insulating material, such as gloves; one requires a special capacitive stylus, or a special-application glove with an embroidered patch of conductive thread passing through it and contacting the user's fingertip. This disadvantage especially affects usability in consumer electronics, such as touch tablet PCs and capacitive smart-phones in cold weather.Display Panel quality
The screen size is one of the first things that a tablet buyer looks for. But what most lay users overlook is the technology behind the display. A salesman will throw seemingly confusing terms such as TFT, LCD, AMOLED, OLED, SLCD at the customer. Here's a list of the different types of mobile displays and an explanation of the technology behind them.TFT LCD Display:
Thin film transistor liquid crystal display (TFT LCD) is a variant of liquid crystal display (LCD). It uses thin-film transistor (TFT) technology to enhance image quality. It is the most common display technology used in mobile phones. It offers better image quality and higher resolutions as compared to earlier generation LCD displays. The only limitations are narrow viewing angles and poor visibility in direct light or sunlight. Further, large TFT displays consume more power and hence, are not battery-friendly. As this display technology is cheaper to manufacture, these are most commonly found on budget devices.IPS LCD:
IPS (in-plane switching) LCD offers better display quality than normal TFT LCD display. It offers wider viewing angles and consumes less power, which in turn gives a much improved battery life. This technology is costlier than normal TFT LCD and hence, is found only on high-end devices. Apple uses a high resolution (640x960 pixels) version of IPS LCD in its iPhone 4, which is also called Retina Display because of its excellent picture quality. Super LCD (SLCD):
It is an upgradade of the erstwhile LCD technology. While both display technologies are efficient with colours and brightness, SLCD scores over AMOLED in very sunny conditions. SLCD gives warmer colour tones and has better colour definition than AMOLED (described below) display technology. OLED Display:
OLED (Organic Light Emitting Diode) display technology is much better than LCD display technology because of its excellent colour reproduction, faster response times, wider viewing angles, higher brightness and extremely light weight designs. AMOLED Display:
There is no substantial difference between the two - OLED AND AMOLED (Active-Matrix Organic Light-Emitting Diode). Active Matrix, which is a method for controlling individual pixels. AMOLED display technology is a type of OLED display for mobiles and is rapidly gaining popularity in high end smartphone segment. AMOLED screens include all the attributes of an OLED display like excellent colour reproduction, faster response times, wider viewing angles, higher brightness and extremely light weight designs. However, in terms of vibrancy and brilliance, AMOLED beats SLCD display technology. There are many high-end phones using this technolgoy like Nokia N8. If you can shell out money, it is suggested to opt for AMOLED display over TFT LCD. Super AMOLED Display:
Super AMOLED display technology is an advanced version of AMOLED display. Developed by Samsung, it is said to be the thinnest display technology in the market. Super AMOLED display is much more responsive than an AMOLED display. Samsung top-of-the-line Galaxy SII comes engineered with Super AMOLED display technology. Retina Display:
Retina Display is a term used by Apple for its high resolution (640x960 pixels) IPS LCD display technology used in iPhone4. The company calls it the Retina display because its pixels cannot be individually identified by a human eye, thereby making the display super sharp, text more crisp and pictures more clear.
Very cheap display panels may be made from plastic and prone to pick up scratches in everyday use whereas top end devices may use Gorilla Glass which features exceptional damage resistance to the scratches, drops, and bumps of everyday use.Device Connectivity
Many tablet PCs have adopted the micro-usb standard which is also the virtual standard across most modern smart-phones. In many cases this may provide the means of charging the device and also of connecting external devices, or to connect to your PC. Currently the Scroll range of tablets uses the mini usb type of connection for external devices and to allow a trickle-charge - although use of the mains charger is recommended.
Many, but not all Scroll tablets, (usually those with only a single usb connection) require a special lead which is not always supplied with the tablet - to allow connection of slave devices such as Flash drive or external keyboard, although this special lead is not required for host devices such as your PC.
This special lead is called an “On The Go” lead or OTG and if your tablet only has a single usb socket then it is likely you will not be able to make external slave devices work without an OTG adaptor/lead as it is specially wired in a manner to trigger automatic switching inside the tablets usb circuitry to supply a host voltage supply to your slave devices. It is important to note that a current limit exists of 500ma which may not be sufficient to power an external hard drive so some power hungry external devices may need their own external power source to work properly or at all. Data Communication:
Tablets usually communicate using either a mobile network supplier or wifi service. Not all tablets are mobile network enabled but some can use 3G mobile dongles and there are discussions on this forum about how to do this. Most tablets have WIFI connectivity and simply logging on to your ISP and entering your Service Set Identifier (SSID) is usually all you need to get connected.The Battery:
There is a very comprehensive excellent article on the Forum written by Charlie here: Everything you wanted to know about Li-Ion batteriesLink
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