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To study the specification and working of LED TV

 

 

OBJECT: - To study the specification and working of LED TV.

APPARATUS:- Signal process board,backlight driving circuit,LCD TV panel,LED TV panel,standby power,rectifier.

THEORY:- LED TVs (light-emitting diode televisions) are considered more enhanced LCD (liquid crystal display) televisions because of their more precise picture outputs and power consumption functions. LED televisions use technology similar to that of LCDs, but the only major difference within their architecture is inclusion of LEDs behind their visual panels (or screens), which make their graphics sharper and more visible. In other words, the enhanced functionality of LED televisions is the tiny light-emitting diodes that produce an illuminating effect upon the provision of current

WORKING:- An LED display is a flat panel display, which uses an array of light-emitting diodes as a video display. An LED panel is a small display, or a component of a larger display. They are typically used outdoors in store signs and billboards, and in recent years have also become commonly used in destination signs on public transport vehicles or even as part of transparent glass area. LED panels are sometimes used as form of lighting, for the purpose of general illuminationtask lighting, or even stage lighting rather than display. All televisions work through back-lit projection from a light source and onto the display screen. Older televisions use standard cathode ray tubes that are set in the rear of the television and project light onto the screen, while LED televisions replace the tube with small light emitting diodes to present light. LEDs are much smaller than cathode ray tubes, allowing for lighter and thinner televisions to be constructed. LEDs are more practical light sources that permit better projection of darker colours than old CRT television sets. There are two types of LED televisions:

Edge LED lighting:- Edge LED lighting televisions combine a series of light-emitting diodes set around the perimeter of the screen with a light-diffusing panel that spreads light from the outer edge of the set to the middle of the screen. Edge LED televisions do not allow the same robust contrast of RGB LED televisions, but they are built in very thin sets which are exceptionally lightweight and inexpensive.

RGB LED lighting:- RGB LED televisions utilize light-emitting diodes set behind the television screen, allowing for regional dimming while delivering more vibrant colour. These types of televisions offer a greater contrast between black and white colour projections. The disadvantages of these types of televisions is that they are more expensive than edge LED televisions and due to the LEDs covering the entire back of the projection screen, RGB models are also heavier.

LED televisions are robust sets for high-definition picture delivery, but there are subtle differences in televisions built with this technology. Take the time to consider these differences before making a new television purchase.

CIRCUIT DIAGRAM:-

Fig:-14(a)

Fig: 14(b)

FIG:-14(c) SCIENTECH 2651A

TECHNICAL SPECIFICATIONS:-

Display Type: LED, HD

Screen Size: 20 Inch (50cm)

Display Resolution: 1600 X 900 pixels

Contrast Ratio: Mega Contrast Ratio

Display Color: 16.7 Million Display Colours

Viewing Angle: 170 (H) X 170 (V)

Refresh Rate: 50 Hz

Video Interface: Video Input/ VGA input

Audio Interface: RCA L & R

Audio Output Power: 8W X 2

Receiving System: PAL BG/I/DK and NTSC

Channel Coverage: VHF-2-12; UHF21-69; CATV (X~Z+2, S11S41)

Antenna Impedance: 75? Unbalanced

Application: Colour Television/ PC Monitor

Connectivity                     

USB: 1 X USB 2.0 (MPEG, JPEG, MP3)

HDMI: Yes (1 X HDMI)

Other Connectivity: RF In, AV In. Ypbpr In, VGA In, VGA Audio In,

AV out

Composite A/V: Yes

Component Video: Yes

Analog Audio: Yes

Test Points: 55 no’s

Switched Faults: 50 no’s

Remote Battery: UM-4, “AAA” 1.5V (2 no’s)

Mains Supply: 110-260V AC ± 10%, 50/60Hz

Power Consumption: 35W

Weight: 11 Kg (approximately)

Dimension: W430 X D252 X H82

Included Accessories: Remote, Mains cord, 34 Pin FRC cable,

15 Pin D type cable each 1 no.

Important factors to consider when evaluating an LED:

Ø  Refresh Rate: - The refresh rate, expressed in Hertz (Hz), describes how many times per second a picture is refreshed on the screen. A typical rate for HD TVs today is 120 Hz (120 refreshes per second). However, higher (or faster) refresh rates, such as 240 Hz, are better for displaying 3D content. Faster refresh rates used in LCDs can also help reduce some picture distortion or blur that can occur in scenes with fast-moving subjects, such as sporting events. Beware of terms like "effective refresh," which means the manufacturer uses other techniques to make the image appear to be more solid but does not in fact use a higher refresh rate.

Ø  Screen Resolution:- Resolution describes the sharpness of the TV picture, usually in terms of horizontal lines of resolution or lines of pixels. A bargain HD set may support only 720p, which means the set displays 720 lines scanned progressively (or in a single pass). Most HD TVs today, however, support the higher — and therefore better — 1080p HD format, which has 1080 lines of resolution (also called "Full HD").

Ø  Smart TVs and Connected TVs:- Rather than using a set-top box like Roku or a game console, smart TVs have an Internet connection and their own apps for online streaming services, such as Netflix. These programs are usually specific to the TV manufacturer (there is no standard operating system, like iOS or Android). So the range of online services offered varies widely. Some sets include apps for Face book and Twitter; others don't. Smart TVs tend to have built-in Wi-Fi to connect to your home network, but check first. A few models still require an Ethernet connection.

PRECAUTIONS:-

1)      Connect the devices properly.

2)      Use an uncluttered and clean work area to do the experiment

RESULT:-We have studied the working and specifications of 20 inch LED TV.

QUESTIONS:-

1)      What is LED TV

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