tft display arduino calculator using gfx tftlcd brands

Arduino development boards always help us to build a project easily and make it look more attractive. Programming an LCD with touch functionality may sound like a complicated task, but it can be made very easy by using Arduino libraries and extension modules. In this project, we will use a 3.5" Arduino TFT LCD to build an Arduino touchscreen calculator that can perform all basic calculations such as addition, subtraction, division, and multiplication.

Before we dive into the project, it is important to understand how this 3.5" TFT LCD module works and the model number used. Let"s take a look at the pinout of this 3.5" TFT LCD module.

As you can see, the module has 28 pins and fits perfectly into any Arduino Uno / Arduino Mega development board. The table below gives a description of these pins.

As you can see, the module pins can be divided into four main categories, namely LCD command pins, LCD data pins, SD card pins and power pins, we don"t need to know the details of how these pins work because they will be implemented by the Arduino library.

You can also find an SD card slot on the bottom of the module shown above. This slot can be used to load an SD card with bmp image files, which can be displayed on our TFT LCD screen using the Arduino program.

Another important thing to keep in mind is your interface IC. there are many types of TFT modules on the market from Adafruit TFT LCD modules to cheap Chinese clones. A program that fits an Adafruit expansion board may not be the same for a Chinese expansion board. Therefore, it is very important to know which type of LCD LCD you are holding. This detail must be obtained from the supplier. If you have a cheap clone like mine, then it most likely uses driver IC ili9341. You can follow the official Arduino tutorial to try some basic example programs to get familiar with this LCD.

If you intend to use the touch screen function of a TFT LCD module, it must be calibrated to work properly. An LCD screen that is not calibrated is unlikely to work properly; for example, you may touch in one place and the TFT may think it is touching somewhere else. These calibration results are not the same for all boards, so you will have to do this work yourself.

The 3.5" TFT LCD is a great Arduino expansion board. You can push the LCD directly onto the top of the Arduino Uno and have it match the pins perfectly and slide them in. However, for safety reasons, the programming terminals of the Arduino UNO must use small insulating tape in case the terminals come into contact with your TFT LCD screen. the LCD assembled to the UNO development board looks like the following.

We use the SPFD5408 library to ensure that the arduino calculator code works properly. This is a modified Adafruit library that works seamlessly with our LCD TFT module. You can view the full program at the end of this article.

Now, open the Arduino IDE and select Sketch -> Include Librarey -> Add .ZIP library. a browser window will open to navigate to the ZIP file and click "OK". If successful, you should notice "Library added to your Libraries" in the bottom left corner of your Arduino.

Now you can use the following code in the Arduino IDE and upload it to Arduino UNO to get the touchscreen calculator working. Further down the page, I"ll explain the code in small segments.

As we know, TFT LCD screens can display many colors, all of which must be entered as hexadecimal values. To make it more readable, we assign these values to a variable as shown below.

Okay, now we can move on to the programming part. This program involves three parts. One is to create a user interface for the calculator using buttons and displays. Then, detect the buttons based on user touch and finally calculate the results and display them. Let"s go through them one by one.

Here you can get creative to design the user interface of the calculator. I simply made the basic layout of the calculator with 16 buttons and a display unit. You must build the design as if you were drawing something on an MS drawing board. The added libraries will allow you to draw lines, rectangles, circles, characters, strings and more in any of the preferred colors. You can learn about the available features from this article.

Another challenging task is to detect the user"s touch. Every time the user touches something, we are able to know the X and Y position of the pixel he touched. This value can be displayed on the serial monitor using println, as shown below.

The final step is to calculate the results and display them on the TFT LCD screen. The arduino calculator can only perform two numeric operations. These two numbers are named as variables "Num1" and "Num2". The variable "Number" is given and taken from Num1 and Num2, and the result is obtained.

The process of working with this Arduino touch screen calculator is very simple. You need to upload the following code to the Arduino development board and then power it up. At this point, a calculator will be displayed on the LCD screen.

In this tutorial we are going to learn how to make Arduino Calculator with TFT Display. Our calculator’s precision is up to two decimal points and you can add, subtract, multiply or divide up to 4 digit per number. Obviously you can add more number of digits if you want.

You have to just add number by touching on screen, maximum digits per number allowable is 4 and then select operator and add again second number, press on equal. Finally, you got the result on screen, Congratulation you have made your own Arduino Calculator with TFT Display.

After uploading the code you"ll able to see the calculator running in your display as mine and now you can perform basic mathematics calculations on this. So have fun making your own calculator with Arduino UNO.

Arduino has always helped to build projects easily and make them look more attractive.  Programming an LCD screen with touch screen option might sound as a complicated task, but the Arduino libraries and shields had made it really easy. In this project we will use a 2.4” Arduino TFT LCD screen to build our own Arduino Touch Screen calculator that could perform all basic calculations like Addition, Subtraction, Division and Multiplication.

Before we actually dive into the project it is important to know, how this 2.4” TFT LCD Module works and what are the types present in it. Let us take a look at the pinouts of this 2.4” TFT LCD screen module.

As you can see there are 28 pins which will perfectly fit into any Arduino Uno / Arduino Mega Board. A small classification of these pins is given in the table below.

As you can see the pins can be classified in to four main classifications such as LCD Command Pins, LCD Data Pins, SD Card Pins and Power Pins, We need not know much about the detailed working of these pins since they will be take care by our Arduino Library.

You can also find an SD card slot at the bottom of the module shown above, which can be used to load an SD card with bmp image files, and these images can be displayed in our TFT LCD screen using the Arduino Program.

Another important thing to note is your Interface IC. There are many types of TFT modules available in the market starting from the original Adafruit TFT LCD module to cheap Chinese clones. A program which works perfectly for your Adafruit shield might not work the same for Chinese breakout boards. So, it is very important to know which types of LCD display your are holding in hand. This detail has to be obtained from the vendor. If you are having a cheap clone like mine then it is most probably using the ili9341 driver IC.You can follow this TFT LCD interfacing with Arduino tutorial to try out some basic example programs and get comfortable with the LCD screen. Also check out our other TFT LCD projects with Arduino here:

If you planning to use the touch screen function of your TFT LCD module, then you have to calibrate it to make it work properly.  A LCD screen without calibration might work unlikely, for instance you might touch at one place and the TFT might respond for a touch at some other place. These calibrations results will not be similar for all boards and hence you are left on your own to do this.

The 2.4” TFT LCD screen is a perfect Arduino Shield. You can directly push the LCD screen on top of the Arduino Uno and it will perfectly match with the pins and slid in through. However, as matters of safety cover the Programming terminal of your Arduino UNO with a small insulation tape, just in case if the terminal comes in contact with your TFT LCD screen. The LCD assembled on UNO will look something like this below.

We are using the SPFD5408 Library to get this arduino calculator code working. This is a modified library of Adafruit and can work seamlessly with our LCD TFT Module. You can check the complete program at the end of this Article.

Now, open Arduino IDE and select Sketch -> Include Librarey -> Add .ZIP library. A browser window will open navigate to the ZIP file and click “OK”. You should notice “Library added to your Libraries” on the bottom-left corner of Arduino, if successful. A detailed guide to do the same is given in the Interfacing Tutorial.

Now, you can use the code below in your Arduino IDE and upload it to your Arduino UNO for the Touch Screen Calculator to work. Further down, I have explained the code into small segments.

As we know the TFT LCD screen can display a lot of colours, all these colours have to be entered in hex value. To make it more human readable we assign these values to a variable as shown below.

Okay now, we can get into the programming part. There are three sections involved in this program. One is creating a UI of a calculator with buttons and display. Then, detecting the buttons based on the users touch and finally calculating the results and display them. Let us get through them one by one.

This is where you can use a lot of your creativity to design the User Interface of calculator. I have simply made a basic layout of a calculator with 16 Buttons and one display unit. You have to construct the design just like you will draw something on MS paint. The libraries added will allow you to draw Lines, Rectangle, Circles, Chars, Strings and lot more of any preferred colour. You can understand the available functions from this article.

I have used the line and box drawing abilities to design an UI which looks very similar to the 90’s calculator.  Each box has a width and height of 60 pixels.

Another challenging task is detecting the user touch. Every time the user touches somewhere we will able to how where the X and Y position of the pixel he touched. This value can be displayed on the serial monitor using the println as shown below.

The final step is to calculate the result and display them on TFT LCD Screen. This arduino calculator can perform operation with 2 numbers only. These two numbers are named as variables “Num1” and “Num2”. The variable “Number” gives and takes value from Num1 and Num2 and also bears the result.

The working of this Arduino Touch Screen Calculator is simple. You have to upload the below given code on your Arduino and fire it up. You get the calculator displayed on your LCD screen.

Draw buttons for digits and operators and the display field of the calculator. All digits and operator buttons have the same size. So, the co-ordinates of each button can be calculated in the program.

The display is driven by a ST7735R controller ( ST7735R-specifications.pdf (2.1 MB) ), can be used in a “slow” and a “fast” write mode, and is 3.3V/5V compatible.

Adafruit_ST7735 is the library we need to pair with the graphics library for hardware specific functions of the ST7735 TFT Display/SD-Card controller.

In the file dialog select the downloaded ZIP file and your library will be installed automatically. This will automatically install the library for you (requires Arduino 1.0.5 or newer). Restarting your Arduino software is recommended as it will make the examples visible in the examples menu.

The easiest way to remedy this is by extracting the GitHub ZIP file. Place the files in a directory with the proper library name (Adafruit_GFX, Adafruit_ST7735 or SD) and zip the folder (Adafruit_GFX, Adafruit_ST7735.zip, SD.zip). Now the Arduino software can read and install the library automatically for you.

Basically, besides the obvious backlight, we tell the controller first what we are talking to with the CS pins. CS(TFT) selects data to be for the Display, and CS(SD) to set data for the SD-Card. Data is written to the selected device through SDA (display) or MOSI (SD-Card). Data is read from the SD-Card through MISO.

So when using both display and SD-Card, and utilizing the Adafruit libraries with a SainSmart display, you will need to connect SDA to MOSI, and SCL to SCLK.

As mentioned before, the display has a SLOW and a FAST mode, each serving it’s own purpose. Do some experiments with both speeds to determine which one works for your application. Of course, the need of particular Arduino pins plays a role in this decision as well …

Note: Adafruit displays can have different colored tabs on the transparent label on your display. You might need to adapt your code if your display shows a little odd shift. I noticed that my SainSmart display (gree tab) behaves best with the code for the black tab – try them out to see which one works best for yours.

Low Speed display is about 1/5 of the speed of High Speed display, which makes it only suitable for particular purposes, but at least the SPI pins of the Arduino are available.

After connecting the display in Low Speed configuration, you can load the first example from the Arduino Software (“File” “Example” “Adafruit_ST7735” –  recommend starting with the “graphictest“).

Below the code parts for a LOW SPEED display (pay attention to the highlighted lines) – keep in mind that the names of the pins in the code are based on the Adafruit display:

You can name your BMP file “parrot.bmp” or modify the Sketch to have the proper filename (in “spitftbitmap” line 70, and in “soft_spitftbitmap” line 74).

#define SD_CS 4 // Chip select line for SD card#define TFT_CS 10 // Chip select line for TFT display#define TFT_DC 9 // Data/command line for TFT#define TFT_RST 8 // Reset line for TFT (or connect to +5V)

#define SD_CS 4 // Chip select line for SD card#define TFT_CS 10 // Chip select line for TFT display#define TFT_DC 9 // Data/command line for TFT#define TFT_RST 8 // Reset line for TFT (or connect to +5V)

As you have seen before the Adafruit_GFX library (supported by the Adafruit_ST7735 library) makes this easy for us – More information can be found at the GFX Reference page.

To use this in your Arduino Sketch: The first 2 characters represent RED, the second set of two characters is for GREEN and the last 2 characters represent BLUE. Add ‘0x’ in front of each of these hex values when using them (‘0x’ designates a hexadecimal value).

This function is used to indicate what corner of your display is considered (0,0), which in essence rotates the coordinate system 0, 90, 180 or 270 degrees.

However, if your application needs your screen sideways, then you’d want to rotate the screen 90 degrees, effectively changing the display from a 128×160 pixel (WxH) screen to a 160×128 pixel display. Valid values are: 0 (0 degrees), 1 (90 degrees), 2 (180 degrees) and 3 (270 degrees).

Based on these functions, I did create a little demo to show what these functions do. Either download the file or just copy the code and paste it into an empty Arduino Sketch.

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- The TFT LCD PCB adapter for Mega is compatible with the Arduino pins, the user can directly connect the TFT LCD PCB - Adapter on the shield and stand on the Arduino board. It can be used with a Mega2560 and LCD screen.

PCF8574A - & gt; the default address 0x3F - You can change anyone between 0x20 and 0x27 depending on whether or not you have soldered pins A0 A1 A2 - With this module the communication between the Arduino and the LCD It is only made through two outputs, SDA and SCL

- Up to 8 LCD screens can be connected to the same I2C bus choosing a different address - Ideal for projects with ARDUINO and Raspberry Pi platforms - You can use it with PIC, AVR, STM32

- The TFT LCD PCB adapter for UNO is compatible with the Arduino pins, the user can plug directly the TFT LCD PCB adapter into the shield and placed on the Arduino board. - Can be used with a UNO and LCD screen

- Conectar la pantalla LCD TFT 2.4 SPI con el módulo UNO Visualizar gráficos y textos en la pantalla LCD TFT 2.4 SPI Programar una calculadora táctil en la pantalla LCD TFT 2.4 SPI

- The TFT LCD PCB adapter for Mega is compatible with the Arduino pins, the user can directly connect the TFT LCD PCB - Adapter on the shield and stand on the Arduino board. It can be used with a Mega2560 and LCD screen.

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Pixel, also called Picture Element, A pixel is the smallest unit of a digital image or graphic that can be displayed and represented on a digital display device. A pixel is the basic logical unit in digital graphics. Pixels are combined to form a complete image, video, text, or any visible thing on a computer display

LCD display doesn’t operate the same way as CRT displays , which fires electrons at a glass screen, a LCD display has individual pixels arranged in a rectangular grid. Each pixel has RGB(Red, Green, Blue) sub-pixel that can be turned on or off. When all of a pixel’s sub-pixels are turned off, it appears black. When all the sub-pixels are turned on 100%, it appears white. By adjusting the individual levels of red, green, and blue light, millions of color combinations are possible

The pixels of the LCD screen were made by circuitry and electrodes of the backplane. Each sub-pixel contains a TFT (Thin Film Transistor) element.  These structures are formed by depositing various materials (metals and silicon) on to the glass substrate that will become one part of the complete display “stack,” and then making them through photolithography. For more information about TFT LCDs, please refer to “

The etched pixels by photolith process are the Native Resolution. Actually, all the flat panel displays, LCD, OLED, Plasma etc.) have native resolution which are different from CRT monitors

Although we can define a LCD display with resolution, a Full HD resolution on screen size of a 15” monitor or a 27” monitor will show different. The screen “fineness” is very important for some application, like medical, or even our cell phone. If the display “fineness” is not enough, the display will look “pixelized” which is unable to show details.

But you see other lower resolution available, that is because video cards are doing the trick. A video card can display a lower LCD screen resolution than the LCD’s built-in native resolution. The video cards can combine the pixels and turn a higher resolution into lower resolution, or just use part of the full screen. But video cards can’t do the magic to exceed the native resolution.

Special names by individual companies: Apple Macbook Pro Retina 6K display, Acer Nitro, ASUS Pro Art , ViewSonic Elite, ASUS TUF ,Samsung edge Infinity-O Display etc.

This resource will discuss the options for graphics controllers for interfacing a display with a high- speed interface. The high-speed interfaces can often benefit from a graphics controller in addition to the central controller to make signal timing more manageable. These interfaces have more demanding requirements on a microcontroller, such as a fast oscillator for the input clocking signal, data signals and synchronization signals. Some examples of high-speed display interfaces would be RGB DPI, LVDS and MIPI DSI. If a microcontroller does not meet the requirements for the display interface, an additional graphics controller chip can be implemented to provide the timing signals and memory to the display.

In addition to controlling the signals and providing memory for the displays frame buffer, an external graphics controller offers a different interface for programming the device. The graphics controller will convert the input signal from the programming controller to match the interface of the display. This can make the connection between graphics controller and the logic controller less intensive. The connection interface will often be offered with lower clocking speeds and smaller bit-width data sizes (SPI, I2C, MCU). This lessens the demand on the microcontroller that would otherwise need to provide these signals, memory, and pin connections.

Three high speed display interfaces will be reviewed in this application. These interfaces are the 24-bit RGB display parallel interface, the MIPI DSI interface and the LVDS interface. An example of the RGB parallel interface will be highlighted to specify requirements of high-speed interfaces and how this becomes an issue for some microcontrollers. Graphics controllers will be offered as an alternative for controllers that do not meet the requirements of the interfaces discussed.

To elaborate, consider an 800x480 TFT display with a 24-bit RGB parallel interface. This size display would have a typical clock frequency requirement of about 31MHz. This is how often the 24-bits of data will be transmitted to the display. Clock frequency is calculated as follows:

The clock would need to be provided from the microcontroller as an input signal to the display. As well as a horizontal sync parameter for every row of pixels (including the timing porch parameters) and a vertical sync for every frame at a refresh rate of about 60Hz. Depending on the display there could also be a “data enable” signal, triggered for each set of active data. For reference the ATmega AVR controller common in the Arduino Uno has a typical frequency of 8-16MHz and therefor would be incompatible for the RGB parallel interface.

The minimum memory needed to display one frame of pixels is known as the frame buffer. The frame buffer is calculated by the resolution and the color depth used for the display. The color depth is how many bits are transmitted per pixel, commonly abbreviated as bpp. In continuation with the example, suppose the display is set to use all 24 data lines to send 24-bits of RGB data per pixel. This is known as RGB888 (8bits R, 8bits B, 8bit G) and has a color range of 16.7M colors. The calculation of the frame buffer would be as follows:

This is the amount of memory needed for a full frame of pixels. The frame buffer is usually stored in SRAM and for reference the Arduino AVR mentioned previously only provides 2kB of SRAM. It is important to note that the displays built in controller IC will sometimes offer internal SRAM provided for the frame buffer. It is necessary to check the specification sheet of the IC of the display to verify if this memory is offered.

To determine which graphics controller to choose, we need to assess which requirements need to be fulfilled. One controller that is commonly used is the RA8875. This controller is programmed through a 4- wire SPI interface to send the RGB data to the display. This controller would reduce the amount of pin connections and is programmable through a lower frequency interface such as SPI.

This chip doesoffer a PLL clock frequency multiplier; however, it is not capable of producing a pixel clock frequency that supports 24-bpp at a resolution of 800x480 pixels. In addition, this chip offers 768kB of RAM for the frame buffer which is insufficientfor the current example. This controller would be better suited for a display with lower resolution or a display that is set to a lower color depth such as RGB565 (16-bpp).

This controller would be a good choice for a display of this resolution, color depth and communication interface. This would support an AVR if the 8-bit MCU communication interface is chosen. If a faster interface, such as the 16/18/24-bit MCU interface, is used to communicate with this controller, the AVR would be insufficient. An ARM microcontroller is often a better option to consider even with the addition of a graphics controlling chip.

A different option for the RGB parallel interface is to use the LT8619b chip which communicates with the displays over an HDMI interface. This chip supports up to 24-bit color depth and up to 4k resolution. This controller is offered by Focus LCDs on the HDMI module boards available on our website, FocusLCDs.com. These chips are compatible with two interfaces, RGB parallel and LVDS. This would be a good choice if using a single board computer or a processor with a HDMI connection port.

The MIPI display serial interface requires high-speed differential signals to be provided at a rate of 1Gb/s depending on resolution and number of data lanes used. The MIPI interface is commonly used for cellphone displays. One graphics controller for the MIPI interface is the SSD2828 controller. This controller has a 4-lane MIPI interface and can provide the display with the high speed and low power signals needed. This controller also offers 27.6Mb of memory for the frame buffer which supports displays with resolution up to 1200x1920 pixels. Similar Solomon chips of the same series offer different supported resolutions. This controller converts a 24-bit RGB interface into the 4-lane MIPI interface.

High speed interfaces are desirable for applications with high resolution and high-speed data transfer. It often becomes necessary to support the microcontroller with a chip specifically designed for this task. This makes programming and timing the interface easier through a lower frequency interface to indicate the specifications of the display. This note offers only a few examples of high-speed interface graphics controllers. There are many graphics controllers available that can meet the demands of these interfaces.

The most significant attributes to look for when choosing a graphics controller will be memory, speed, and pin requirements. The memory requirements are a minimum set by the frame buffer and color depth chosen. The speed of data transmission is set by the interface used and the resolution of the display to maintain a refresh rate of 60Hz. The pin requirements are defined by the display, interface and availability provided by the central controller for the application. Choosing a “conversion” interface (RGB to SPI, LVDS to MCU) between the graphics controller and the high-speed interface of the display is reliant on the capabilities of the microcontroller or processor being used to send the commands to the graphics controller.

Additionally, it is always important to check the capabilities of the internal IC of the display. Some displays will offer internal memory for the frame buffer or an internal oscillator to meet these requirements. These features will be described in the specification sheet of the displays controller which are available on

Buyers and others who are developing systems that incorporate FocusLCDs products (collectively, “Designers”) understand and agree that Designers remain responsible for using their independent analysis, evaluation and judgment in designing their applications and that Designers have full and exclusive responsibility to assure the safety of Designers" applications and compliance of their applications (and of all FocusLCDs products used in or for Designers’ applications) with all applicable regulations, laws and other applicable requirements.

Designer agrees that prior to using or distributing any applications that include FocusLCDs products, Designer will thoroughly test such applications and the functionality of such FocusLCDs products as used in such applications.

A thin-film-transistor liquid-crystal display (TFT LCD) is a variant of a liquid-crystal display that uses thin-film-transistor technologyactive matrix LCD, in contrast to passive matrix LCDs or simple, direct-driven (i.e. with segments directly connected to electronics outside the LCD) LCDs with a few segments.

In February 1957, John Wallmark of RCA filed a patent for a thin film MOSFET. Paul K. Weimer, also of RCA implemented Wallmark"s ideas and developed the thin-film transistor (TFT) in 1962, a type of MOSFET distinct from the standard bulk MOSFET. It was made with thin films of cadmium selenide and cadmium sulfide. The idea of a TFT-based liquid-crystal display (LCD) was conceived by Bernard Lechner of RCA Laboratories in 1968. In 1971, Lechner, F. J. Marlowe, E. O. Nester and J. Tults demonstrated a 2-by-18 matrix display driven by a hybrid circuit using the dynamic scattering mode of LCDs.T. Peter Brody, J. A. Asars and G. D. Dixon at Westinghouse Research Laboratories developed a CdSe (cadmium selenide) TFT, which they used to demonstrate the first CdSe thin-film-transistor liquid-crystal display (TFT LCD).active-matrix liquid-crystal display (AM LCD) using CdSe TFTs in 1974, and then Brody coined the term "active matrix" in 1975.high-resolution and high-quality electronic visual display devices use TFT-based active matrix displays.

The liquid crystal displays used in calculators and other devices with similarly simple displays have direct-driven image elements, and therefore a voltage can be easily applied across just one segment of these types of displays without interfering with the other segments. This would be impractical for a large display, because it would have a large number of (color) picture elements (pixels), and thus it would require millions of connections, both top and bottom for each one of the three colors (red, green and blue) of every pixel. To avoid this issue, the pixels are addressed in rows and columns, reducing the connection count from millions down to thousands. The column and row wires attach to transistor switches, one for each pixel. The one-way current passing characteristic of the transistor prevents the charge that is being applied to each pixel from being drained between refreshes to a display"s image. Each pixel is a small capacitor with a layer of insulating liquid crystal sandwiched between transparent conductive ITO layers.

The circuit layout process of a TFT-LCD is very similar to that of semiconductor products. However, rather than fabricating the transistors from silicon, that is formed into a crystalline silicon wafer, they are made from a thin film of amorphous silicon that is deposited on a glass panel. The silicon layer for TFT-LCDs is typically deposited using the PECVD process.

Polycrystalline silicon is sometimes used in displays requiring higher TFT performance. Examples include small high-resolution displays such as those found in projectors or viewfinders. Amorphous silicon-based TFTs are by far the most common, due to their lower production cost, whereas polycrystalline silicon TFTs are more costly and much more difficult to produce.

The twisted nematic display is one of the oldest and frequently cheapest kind of LCD display technologies available. TN displays benefit from fast pixel response times and less smearing than other LCD display technology, but suffer from poor color reproduction and limited viewing angles, especially in the vertical direction. Colors will shift, potentially to the point of completely inverting, when viewed at an angle that is not perpendicular to the display. Modern, high end consumer products have developed methods to overcome the technology"s shortcomings, such as RTC (Response Time Compensation / Overdrive) technologies. Modern TN displays can look significantly better than older TN displays from decades earlier, but overall TN has inferior viewing angles and poor color in comparison to other technology.

Most TN panels can represent colors using only six bits per RGB channel, or 18 bit in total, and are unable to display the 16.7 million color shades (24-bit truecolor) that are available using 24-bit color. Instead, these panels display interpolated 24-bit color using a dithering method that combines adjacent pixels to simulate the desired shade. They can also use a form of temporal dithering called Frame Rate Control (FRC), which cycles between different shades with each new frame to simulate an intermediate shade. Such 18 bit panels with dithering are sometimes advertised as having "16.2 million colors". These color simulation methods are noticeable to many people and highly bothersome to some.gamut (often referred to as a percentage of the NTSC 1953 color gamut) are also due to backlighting technology. It is not uncommon for older displays to range from 10% to 26% of the NTSC color gamut, whereas other kind of displays, utilizing more complicated CCFL or LED phosphor formulations or RGB LED backlights, may extend past 100% of the NTSC color gamut, a difference quite perceivable by the human eye.

In 2004, Hydis Technologies Co., Ltd licensed its AFFS patent to Japan"s Hitachi Displays. Hitachi is using AFFS to manufacture high end panels in their product line. In 2006, Hydis also licensed its AFFS to Sanyo Epson Imaging Devices Corporation.

Less expensive PVA panels often use dithering and FRC, whereas super-PVA (S-PVA) panels all use at least 8 bits per color component and do not use color simulation methods.BRAVIA LCD TVs offer 10-bit and xvYCC color support, for example, the Bravia X4500 series. S-PVA also offers fast response times using modern RTC technologies.

A technology developed by Samsung is Super PLS, which bears similarities to IPS panels, has wider viewing angles, better image quality, increased brightness, and lower production costs. PLS technology debuted in the PC display market with the release of the Samsung S27A850 and S24A850 monitors in September 2011.

TFT dual-transistor pixel or cell technology is a reflective-display technology for use in very-low-power-consumption applications such as electronic shelf labels (ESL), digital watches, or metering. DTP involves adding a secondary transistor gate in the single TFT cell to maintain the display of a pixel during a period of 1s without loss of image or without degrading the TFT transistors over time. By slowing the refresh rate of the standard frequency from 60 Hz to 1 Hz, DTP claims to increase the power efficiency by multiple orders of magnitude.

Due to the very high cost of building TFT factories, there are few major OEM panel vendors for large display panels. The glass panel suppliers are as follows:

External consumer display devices like a TFT LCD feature one or more analog VGA, DVI, HDMI, or DisplayPort interface, with many featuring a selection of these interfaces. Inside external display devices there is a controller board that will convert the video signal using color mapping and image scaling usually employing the discrete cosine transform (DCT) in order to convert any video source like CVBS, VGA, DVI, HDMI, etc. into digital RGB at the native resolution of the display panel. In a laptop the graphics chip will directly produce a signal suitable for connection to the built-in TFT display. A control mechanism for the backlight is usually included on the same controller board.

The low level interface of STN, DSTN, or TFT display panels use either single ended TTL 5 V signal for older displays or TTL 3.3 V for slightly newer displays that transmits the pixel clock, horizontal sync, vertical sync, digital red, digital green, digital blue in parallel. Some models (for example the AT070TN92) also feature input/display enable, horizontal scan direction and vertical scan direction signals.

New and large (>15") TFT displays often use LVDS signaling that transmits the same contents as the parallel interface (Hsync, Vsync, RGB) but will put control and RGB bits into a number of serial transmission lines synchronized to a clock whose rate is equal to the pixel rate. LVDS transmits seven bits per clock per data line, with six bits being data and one bit used to signal if the other six bits need to be inverted in order to maintain DC balance. Low-cost TFT displays often have three data lines and therefore only directly support 18 bits per pixel. Upscale displays have four or five data lines to support 24 bits per pixel (truecolor) or 30 bits per pixel respectively. Panel manufacturers are slowly replacing LVDS with Internal DisplayPort and Embedded DisplayPort, which allow sixfold reduction of the number of differential pairs.

The bare display panel will only accept a digital video signal at the resolution determined by the panel pixel matrix designed at manufacture. Some screen panels will ignore the LSB bits of the color information to present a consistent interface (8 bit -> 6 bit/color x3).

With analogue signals like VGA, the display controller also needs to perform a high speed analog to digital conversion. With digital input signals like DVI or HDMI some simple reordering of the bits is needed before feeding it to the rescaler if the input resolution doesn"t match the display panel resolution.

Kawamoto, H. (2012). "The Inventors of TFT Active-Matrix LCD Receive the 2011 IEEE Nishizawa Medal". Journal of Display Technology. 8 (1): 3–4. Bibcode:2012JDisT...8....3K. doi:10.1109/JDT.2011.2177740. ISSN 1551-319X.

Brody, T. Peter; Asars, J. A.; Dixon, G. D. (November 1973). "A 6 × 6 inch 20 lines-per-inch liquid-crystal display panel". 20 (11): 995–1001. Bibcode:1973ITED...20..995B. doi:10.1109/T-ED.1973.17780. ISSN 0018-9383.

K. H. Lee; H. Y. Kim; K. H. Park; S. J. Jang; I. C. Park & J. Y. Lee (June 2006). "A Novel Outdoor Readability of Portable TFT-LCD with AFFS Technology". SID Symposium Digest of Technical Papers. AIP. 37 (1): 1079–82. doi:10.1889/1.2433159. S2CID 129569963.

Kim, Sae-Bom; Kim, Woong-Ki; Chounlamany, Vanseng; Seo, Jaehwan; Yoo, Jisu; Jo, Hun-Je; Jung, Jinho (15 August 2012). "Identification of multi-level toxicity of liquid crystal display wastewater toward Daphnia magna and Moina macrocopa". Journal of Hazardous Materials. Seoul, Korea; Laos, Lao. 227–228: 327–333. doi:10.1016/j.jhazmat.2012.05.059. PMID 22677053.

{"id":4795785936967,"title":"AC 260V 100A Digital LCD Panel Volt AMP Meter Power Energy Ammeter Voltmeter","handle":"ac-260v-100a-digital-lcd-panel-volt-amp-meter-power-energy-ammeter-voltmeter","description":"\u003cspan lang=\"en\"\u003e\u003cspan lang=\"en\"\u003e\u003cspan title=\"Description\nA Function\n1. Electrical parameter measurement function (voltage, current, active power, energy)\n2. Overload alarm function (over power alarm threshold, backlight and power flashing to alarm).\n3. Power alarm threshold preset function (can set power alarm threshold).\n4. Reset energy function.\n5. Store data when power off.\n6. STN whole viewing angleLCD (display voltage, current, active power\/energy at the same time)\n7. Backlight function.\nB. Appearance and Key function\nI. Display Interface\nThe large-screen STN whole viewing angle LCD can display voltage, current, power, energy at the same time.(note: power and energy display can be switched by the key.)\nII.Display format\n\n1.Power: test range: 0~22kW\nwithin 1KW, the display format is 0.0~999.9W;\n1KW and above, the display format is 1000~9999W;\n10kw and above, the display format is 10.0~22.0kW\n2.Energy: test range: 0~9999kWh\nWithin 10KWh, the display format is 0~9999Wh;\n10kWh and above, the display format is 10~9999kWh;\nOver 9999kwh will return 0\n3. Voltage: test range: 80~260V\nDisplay format: 80~260V\n4. Current: test range: 0~100A\nDisplay format: 0.00~99.99A\nIII. Key\n1. Backlight control\nShort press the key to turn on or off the backlight, the backlight has memory function, it can store the on or off state when power off.\n2. Reset energy\nStep1: Long press the key at least3 seconds until the number in energy display area flash, then release the key.\nStep2: If short press the key again, then the energy value is cleared and exit the reset state.If short press the key again, then the energy value will not be cleared and will exit the reset state. If there is no operation on the key within 10 seconds, the energy value will not be cleared and will exit the reset state.\n3. Set power alarm threshold\nStep1: Long press the key at least 3 seconds until the number in power display area flash,then release the key\nStep2: Powerarea display the current power alarm value and the last digit begin to flash, then you can short press the key to plus 1, short press the key can switch the digit which you want to set. The threshold can’t be over 25kw( note: the default value is 25kw)\n\nStep3: After finish the setting, long press the key over 3 seconds or there is no operation over 10 seconds, it will store data automatically and exit the set state.\n4. Power\/Energy switch\nYou can short press the key to switch display the power\/ energy, the display state will be store when power off.\nC. Precautions\n1. This module is suitable for indoor, please do not use outdoor.\n2. Applied load should not exceed the rated power.\n3. Wiring order can’t be wrong.\nD. Specification parameters\n1. Working voltage: 80 ~ 260VAC\n2. Test voltage: 80 ~ 260VAC\n3. Rated power: 22kW\n4. Operating frequency: 45-65Hz\n5. Measurement accuracy: 1.0 grade \n\nPackage Included:\n1PC*\"\u003e\u003cstrong\u003eDescription\u003c\/strong\u003e\u003cbr\u003e\u003cstrong\u003eA Function\u003c\/strong\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/span\u003e\u003c\/span\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan id=\"result_box\" lang=\"en\"\u003e\u003cspan title=\"Description\nA Function\n1. Electrical parameter measurement function (voltage, current, active power, energy)\n2. Overload alarm function (over power alarm threshold, backlight and power flashing to alarm).\n3. Power alarm threshold preset function (can set power alarm threshold).\n4. Reset energy function.\n5. Store data when power off.\n6. STN whole viewing angleLCD (display voltage, current, active power\/energy at the same time)\n7. Backlight function.\nB. Appearance and Key function\nI. Display Interface\nThe large-screen STN whole viewing angle LCD can display voltage, current, power, energy at the same time.(note: power and energy display can be switched by the key.)\nII.Display format\n\n1.Power: test range: 0~22kW\nwithin 1KW, the display format is 0.0~999.9W;\n1KW and above, the display format is 1000~9999W;\n10kw and above, the display format is 10.0~22.0kW\n2.Energy: test range: 0~9999kWh\nWithin 10KWh, the display format is 0~9999Wh;\n10kWh and above, the display format is 10~9999kWh;\nOver 9999kwh will return 0\n3. Voltage: test range: 80~260V\nDisplay format: 80~260V\n4. Current: test range: 0~100A\nDisplay format: 0.00~99.99A\nIII. Key\n1. Backlight control\nShort press the key to turn on or off the backlight, the backlight has memory function, it can store the on or off state when power off.\n2. Reset energy\nStep1: Long press the key at least3 seconds until the number in energy display area flash, then release the key.\nStep2: If short press the key again, then the energy value is cleared and exit the reset state.If short press the key again, then the energy value will not be cleared and will exit the reset state. If there is no operation on the key within 10 seconds, the energy value will not be cleared and will exit the reset state.\n3. Set power alarm threshold\nStep1: Long press the key at least 3 seconds until the number in power display area flash,then release the key\nStep2: Powerarea display the current power alarm value and the last digit begin to flash, then you can short press the key to plus 1, short press the key can switch the digit which you want to set. The threshold can’t be over 25kw( note: the default value is 25kw)\n\nStep3: After finish the setting, long press the key over 3 seconds or there is no operation over 10 seconds, it will store data automatically and exit the set state.\n4. Power\/Energy switch\nYou can short press the key to switch display the power\/ energy, the display state will be store when power off.\nC. Precautions\n1. This module is suitable for indoor, please do not use outdoor.\n2. Applied load should not exceed the rated power.\n3. Wiring order can’t be wrong.\nD. Specification parameters\n1. Working voltage: 80 ~ 260VAC\n2. Test voltage: 80 ~ 260VAC\n3. Rated power: 22kW\n4. Operating frequency: 45-65Hz\n5. Measurement accuracy: 1.0 grade \n\nPackage Included:\n1PC*\"\u003eElectrical parameter measurement function (voltage, current, active power, energy)\u003c\/span\u003e\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan id=\"result_box\" lang=\"en\"\u003e\u003cspan title=\"Description\nA Function\n1. Electrical parameter measurement function (voltage, current, active power, energy)\n2. Overload alarm function (over power alarm threshold, backlight and power flashing to alarm).\n3. Power alarm threshold preset function (can set power alarm threshold).\n4. Reset energy function.\n5. Store data when power off.\n6. STN whole viewing angleLCD (display voltage, current, active power\/energy at the same time)\n7. Backlight function.\nB. Appearance and Key function\nI. Display Interface\nThe large-screen STN whole viewing angle LCD can display voltage, current, power, energy at the same time.(note: power and energy display can be switched by the key.)\nII.Display format\n\n1.Power: test range: 0~22kW\nwithin 1KW, the display format is 0.0~999.9W;\n1KW and above, the display format is 1000~9999W;\n10kw and above, the display format is 10.0~22.0kW\n2.Energy: test range: 0~9999kWh\nWithin 10KWh, the display format is 0~9999Wh;\n10kWh and above, the display format is 10~9999kWh;\nOver 9999kwh will return 0\n3. Voltage: test range: 80~260V\nDisplay format: 80~260V\n4. Current: test range: 0~100A\nDisplay format: 0.00~99.99A\nIII. Key\n1. Backlight control\nShort press the key to turn on or off the backlight, the backlight has memory function, it can store the on or off state when power off.\n2. Reset energy\nStep1: Long press the key at least3 seconds until the number in energy display area flash, then release the key.\nStep2: If short press the key again, then the energy value is cleared and exit the reset state.If short press the key again, then the energy value will not be cleared and will exit the reset state. If there is no operation on the key within 10 seconds, the energy value will not be cleared and will exit the reset state.\n3. Set power alarm threshold\nStep1: Long press the key at least 3 seconds until the number in power display area flash,then release the key\nStep2: Powerarea display the current power alarm value and the last digit begin to flash, then you can short press the key to plus 1, short press the key can switch the digit which you want to set. The threshold can’t be over 25kw( note: the default value is 25kw)\n\nStep3: After finish the setting, long press the key over 3 seconds or there is no operation over 10 seconds, it will store data automatically and exit the set state.\n4. Power\/Energy switch\nYou can short press the key to switch display the power\/ energy, the display state will be store when power off.\nC. Precautions\n1. This module is suitable for indoor, please do not use outdoor.\n2. Applied load should not exceed the rated power.\n3. Wiring order can’t be wrong.\nD. Specification parameters\n1. Working voltage: 80 ~ 260VAC\n2. Test voltage: 80 ~ 260VAC\n3. Rated power: 22kW\n4. Operating frequency: 45-65Hz\n5. Measurement accuracy: 1.0 grade \n\nPackage Included:\n1PC*\"\u003eOverload alarm function (over power alarm threshold, backlight and power flashing to alarm).\u003c\/span\u003e\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan id=\"result_box\" lang=\"en\"\u003e\u003cspan title=\"Description\nA Function\n1. Electrical parameter measurement function (voltage, current, active power, energy)\n2. Overload alarm function (over power alarm threshold, backlight and power flashing to alarm).\n3. Power alarm threshold preset function (can set power alarm threshold).\n4. Reset energy function.\n5. Store data when power off.\n6. STN whole viewing angleLCD (display voltage, current, active power\/energy at the same time)\n7. Backlight function.\nB. Appearance and Key function\nI. Display Interface\nThe large-screen STN whole viewing angle LCD can display voltage, current, power, energy at the same time.(note: power and energy display can be switched by the key.)\nII.Display format\n\n1.Power: test range: 0~22kW\nwithin 1KW, the display format is 0.0~999.9W;\n1KW and above, the display format is 1000~9999W;\n10kw and above, the display format is 10.0~22.0kW\n2.Energy: test range: 0~9999kWh\nWithin 10KWh, the display format is 0~9999Wh;\n10kWh and above, the display format is 10~9999kWh;\nOver 9999kwh will return 0\n3. Voltage: test range: 80~260V\nDisplay format: 80~260V\n4. Current: test range: 0~100A\nDisplay format: 0.00~99.99A\nIII. Key\n1. Backlight control\nShort press the key to turn on or off the backlight, the backlight has memory function, it can store the on or off state when power off.\n2. Reset energy\nStep1: Long press the key at least3 seconds until the number in energy display area flash, then release the key.\nStep2: If short press the key again, then the energy value is cleared and exit the reset state.If short press the key again, then the energy value will not be cleared and will exit the reset state. If there is no operation on the key within 10 seconds, the energy value will not be cleared and will exit the reset state.\n3. Set power alarm threshold\nStep1: Long press the key at least 3 seconds until the number in power display area flash,then release the key\nStep2: Powerarea display the current power alarm value and the last digit begin to flash, then you can short press the key to plus 1, short press the key can switch the digit which you want to set. The threshold can’t be over 25kw( note: the default value is 25kw)\n\nStep3: After finish the setting, long press the key over 3 seconds or there is no operation over 10 seconds, it will store data automatically and exit the set state.\n4. Power\/Energy switch\nYou can short press the key to switch display the power\/ energy, the display state will be store when power off.\nC. Precautions\n1. This module is suitable for indoor, please do not use outdoor.\n2. Applied load should not exceed the rated power.\n3. Wiring order can’t be wrong.\nD. Specification parameters\n1. Working voltage: 80 ~ 260VAC\n2. Test voltage: 80 ~ 260VAC\n3. Rated power: 22kW\n4. Operating frequency: 45-65Hz\n5. Measurement accuracy: 1.0 grade \n\nPackage Included:\n1PC*\"\u003ePower alarm threshold preset function (can set power alarm threshold).\u003c\/span\u003e\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan id=\"result_box\" lang=\"en\"\u003e\u003cspan title=\"Description\nA Function\n1. Electrical parameter measurement function (voltage, current, active power, energy)\n2. Overload alarm function (over power alarm threshold, backlight and power flashing to alarm).\n3. Power alarm threshold preset function (can set power alarm threshold).\n4. Reset energy function.\n5. Store data when power off.\n6. STN whole viewing angleLCD (display voltage, current, active power\/energy at the same time)\n7. Backlight function.\nB. Appearance and Key function\nI. Display Interface\nThe large-screen STN whole viewing angle LCD can display voltage, current, power, energy at the same time.(note: power and energy display can be switched by the key.)\nII.Display format\n\n1.Power: test range: 0~22kW\nwithin 1KW, the display format is 0.0~999.9W;\n1KW and above, the display format is 1000~9999W;\n10kw and above, the display format is 10.0~22.0kW\n2.Energy: test range: 0~9999kWh\nWithin 10KWh, the display format is 0~9999Wh;\n10kWh and above, the display format is 10~9999kWh;\nOver 9999kwh will return 0\n3. Voltage: test range: 80~260V\nDisplay format: 80~260V\n4. Current: test range: 0~100A\nDisplay format: 0.00~99.99A\nIII. Key\n1. Backlight control\nShort press the key to turn on or off the backlight, the backlight has memory function, it can store the on or off state when power off.\n2. Reset energy\nStep1: Long press the key at least3 seconds until the number in energy display area flash, then release the key.\nStep2: If short press the key again, then the energy value is cleared and exit the reset state.If short press the key again, then the energy value will not be cleared and will exit the reset state. If there is no operation on the key within 10 seconds, the energy value will not be cleared and will exit the reset state.\n3. Set power alarm threshold\nStep1: Long press the key at least 3 seconds until the number in power display area flash,then release the key\nStep2: Powerarea display the current power alarm value and the last digit begin to flash, then you can short press the key to plus 1, short press the key can switch the digit which you want to set. The threshold can’t be over 25kw( note: the default value is 25kw)\n\nStep3: After finish the setting, long press the key over 3 seconds or there is no operation over 10 seconds, it will store data automatically and exit the set state.\n4. Power\/Energy switch\nYou can short press the key to switch display the power\/ energy, the display state will be store when power off.\nC. Precautions\n1. This module is suitable for indoor, please do not use outdoor.\n2. Applied load should not exceed the rated power.\n3. Wiring order can’t be wrong.\nD. Specification parameters\n1. Working voltage: 80 ~ 260VAC\n2. Test voltage: 80 ~ 260VAC\n3. Rated power: 22kW\n4. Operating frequency: 45-65Hz\n5. Measurement accuracy: 1.0 grade \n\nPackage Included:\n1PC*\"\u003eReset energy function.\u003c\/span\u003e\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan id=\"result_box\" lang=\"en\"\u003e\u003cspan title=\"Description\nA Function\n1. Electrical parameter measurement function (voltage, current, active power, energy)\n2. Overload alarm function (over power alarm threshold, backlight and power flashing to alarm).\n3. Power alarm threshold preset function (can set power alarm threshold).\n4. Reset energy function.\n5. Store data when power off.\n6. STN whole viewing angleLCD (display voltage, current, active power\/energy at the same time)\n7. Backlight function.\nB. Appearance and Key function\nI. Display Interface\nThe large-screen STN whole viewing angle LCD can display voltage, current, power, energy at the same time.(note: power and energy display can be switched by the key.)\nII.Display format\n\n1.Power: test range: 0~22kW\nwithin 1KW, the display format is 0.0~999.9W;\n1KW and above, the display format is 1000~9999W;\n10kw and above, the display format is 10.0~22.0kW\n2.Energy: test range: 0~9999kWh\nWithin 10KWh, the display format is 0~9999Wh;\n10kWh and above, the display format is 10~9999kWh;\nOver 9999kwh will return 0\n3. Voltage: test range: 80~260V\nDisplay format: 80~260V\n4. Current: test range: 0~100A\nDisplay format: 0.00~99.99A\nIII. Key\n1. Backlight control\nShort press the key to turn on or off the backlight, the backlight has memory function, it can store the on or off state when power off.\n2. Reset energy\nStep1: Long press the key at least3 seconds until the number in energy display area flash, then release the key.\nStep2: If short press the key again, then the energy value is cleared and exit the reset state.If short press the key again, then the energy value will not be cleared and will exit the reset state. If there is no operation on the key within 10 seconds, the energy value will not be cleared and will exit the reset state.\n3. Set power alarm threshold\nStep1: Long press the key at least 3 seconds until the number in power display area flash,then release the key\nStep2: Powerarea display the current power alarm value and the last digit begin to flash, then you can short press the key to plus 1, short press the key can switch the digit which you want to set. The threshold can’t be over 25kw( note: the default value is 25kw)\n\nStep3: After finish the setting, long press the key over 3 seconds or there is no operation over 10 seconds, it will store data automatically and exit the set state.\n4. Power\/Energy switch\nYou can short press the key to switch display the power\/ energy, the display state will be store when power off.\nC. Precautions\n1. This module is suitable for indoor, please do not use outdoor.\n2. Applied load should not exceed the rated power.\n3. Wiring order can’t be wrong.\nD. Specification parameters\n1. Working voltage: 80 ~ 260VAC\n2. Test voltage: 80 ~ 260VAC\n3. Rated power: 22kW\n4. Operating frequency: 45-65Hz\n5. Measurement accuracy: 1.0 grade \n\nPackage Included:\n1PC*\"\u003eStore data when power off.\u003c\/span\u003e\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan id=\"result_box\" lang=\"en\"\u003e\u003cspan title=\"Description\nA Function\n1. Electrical parameter measurement function (voltage, current, active power, energy)\n2. Overload alarm function (over power alarm threshold, backlight and power flashing to alarm).\n3. Power alarm threshold preset function (can set power alarm threshold).\n4. Reset energy function.\n5. Store data when power off.\n6. STN whole viewing angleLCD (display voltage, current, active power\/energy at the same time)\n7. Backlight function.\nB. Appearance and Key function\nI. Display Interface\nThe large-screen STN whole viewing angle LCD can display voltage, current, power, energy at the same time.(note: power and energy display can be switched by the key.)\nII.Display format\n\n1.Power: test range: 0~22kW\nwithin 1KW, the display format is 0.0~999.9W;\n1KW and above, the display format is 1000~9999W;\n10kw and above, the display format is 10.0~22.0kW\n2.Energy: test range: 0~9999kWh\nWithin 10KWh, the display format is 0~9999Wh;\n10kWh and above, the display format is 10~9999kWh;\nOver 9999kwh will return 0\n3. Voltage: test range: 80~260V\nDisplay format: 80~260V\n4. Current: test range: 0~100A\nDisplay format: 0.00~99.99A\nIII. Key\n1. Backlight control\nShort press the key to turn on or off the backlight, the backlight has memory function, it can store the on or off state when power off.\n2. Reset energy\nStep1: Long press the key at least3 seconds until the number in energy display area flash, then release the key.\nStep2: If short press the key again, then the energy value is cleared and exit the reset state.If short press the key again, then the energy value will not be cleared and will exit the reset state. If there is no operation on the key within 10 seconds, the energy value will not be cleared and will exit the reset state.\n3. Set power alarm threshold\nStep1: Long press the key at least 3 seconds until the number in power display area flash,then release the key\nStep2: Powerarea display the current power alarm value and the last digit begin to flash, then you can short press the key to plus 1, short press the key can switch the digit which you want to set. The threshold can’t be over 25kw( note: the default value is 25kw)\n\nStep3: After finish the setting, long press the key over 3 seconds or there is no operation over 10 seconds, it will store data automatically and exit the set state.\n4. Power\/Energy switch\nYou can short press the key to switch display the power\/ energy, the display state will be store when power off.\nC. Precautions\n1. This module is suitable for indoor, please do not use outdoor.\n2. Applied load should not exceed the rated power.\n3. Wiring order can’t be wrong.\nD. Specification parameters\n1. Working voltage: 80 ~ 260VAC\n2. Test voltage: 80 ~ 260VAC\n3. Rated power: 22kW\n4. Operating frequency: 45-65Hz\n5. Measurement accuracy: 1.0 grade \n\nPackage Included:\n1PC*\"\u003eSTN whole viewing angleLCD (display voltage, current, active power\/energy at the same time)\u003c\/span\u003e\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan id=\"result_box\" lang=\"en\"\u003e\u003cspan title=\"Description\nA Function\n1. Electrical parameter measurement function (voltage, current, active power, energy)\n2. Overload alarm function (over power alarm threshold, backlight and power flashing to alarm).\n3. Power alarm threshold preset function (can set power alarm threshold).\n4. Reset energy function.\n5. Store data when power off.\n6. STN whole viewing angleLCD (display voltage, current, active power\/energy at the same time)\n7. Backlight function.\nB. Appearance and Key function\nI. Display Interface\nThe large-screen STN whole viewing angle LCD can display voltage, current, power, energy at the same time.(note: power and energy display can be switched by the key.)\nII.Display format\n\n1.Power: test range: 0~22kW\nwithin 1KW, the display format is 0.0~999.9W;\n1KW and above, the display format is 1000~9999W;\n10kw and above, the display format is 10.0~22.0kW\n2.Energy: test range: 0~9999kWh\nWithin 10KWh, the display format is 0~9999Wh;\n10kWh and above, the display format is 10~9999kWh;\nOver 9999kwh will return 0\n3. Voltage: test range: 80~260V\nDisplay format: 80~260V\n4. Current: test range: 0~100A\nDisplay format: 0.00~99.99A\nIII. Key\n1. Backlight control\nShort press the key to turn on or off the backlight, the backlight has memory function, it can store the on or off state when power off.\n2. Reset energy\nStep1: Long press the key at least3 seconds until the number in energy display area flash, then release the key.\nStep2: If short press the key again, then the energy value is cleared and exit the reset state.If short press the key again, then the energy value will not be cleared and w