In 2014, the production of television sets with a cathode-ray tube was discontinued. Today you will no longer be able to find CRT TVs with a diagonal of 21 inches and above. There are still models with a screen diagonal of 14 inches and less. The time of CRT TVs has passed, and today basically all manufacturers produce LED TVs.

The TV that uses to display the image on the screen cathode ray tube (CRT) aka CRT (Cathode Ray Tube), and is called a CRT or CRT TV... In the CRT, there are three cathode guns (red, green, blue), which fire (analogy with guns) a screen covered with a phosphor, causing a glow. The work of the CRT TV is aimed at controlling these guns. And the perfection of the picture that we see depends on the quality of the picture tube and the quality of the control circuit. Therefore, when choosing a CRT TV, you need to look at the class of the kinescope and the availability of circuit solutions to improve the quality (filters, amplifiers, etc.).

Traditional CRT TVs have been on the market longer than others, so manufacturers have already managed to work out technologies almost to perfection, and thanks to this, you can choose a reliable, well-showing, durable TV. If you will use it to watch mainly TV programs and want to save a little money, then you need to choose a CRT TV. It will serve you more than ten years and such TVs are easier to repair than others.

The appearance of the CRT TV receiver

How to choose a crt TV by characteristics

The main disadvantages of CRT TVs are:

• geometric distortion (for modern TVs in a high price range are almost invisible, especially with flat picture tubes);
• convergence problem (almost invisible for TVs with a high price);
• big sizes (in depth, differently thickness) than LCD and plasma (if there is room for installation, then you can ignore it);
• exposure to magnetic fields (just do not put speakers or other sources of magnetic fields closer than 1 meter);
• screen size limit (up to 38 inches), for a small room a diagonal of 90 centimeters is quite enough;
• harmful effects on humans due to radiation (thanks to modern technologies, it was possible to reduce the amount of CRT so much that you can ignore it);

Scanning 100 Hz in CRT TVs

Another drawback of CRT TV is screen flickering. Due to the introduction of 100 Hz technology, this flicker is almost removed. Then the picture will be stable, which will be especially noticeable when reading small letters, and accordingly the eyes get tired less. With this method, the signal is received from the air with a frequency of 50 Hz, but in a CRT TV 100 Hz frames are remembered and played back twice during the time it takes on a regular TV to play one frame... But there are also disadvantages to this method. On fast scenes, trails will be noticeable, steps will be visible at the edges of the transitions, tremors will be noticeable at the edges of the screen. To eliminate these shortcomings in CRT TVs, various circuit solutions are used. Applying 1-2-1-2 frame sequencing eliminates jitter. Digital filters suppress noise and reduce the trail. Creating intermediate frames inserted between work frames further enhances the picture, making transitions more natural. Therefore, do not rush to choose a CRT TV with 100 Hz sweep. Look at the picture when you quickly change the plot (sports, racing) and then make a decision.

CRT TV sound

If you are not going to buy an additional audio system, but want to listen to high-quality soundtrack, then pay attention to the presence of built-in decoding processors dolby sound on CRT TV.

When buying an expensive crt model, pay attention to the presence of the picture-in-picture and picture-and-picture functions, which allow you to watch two channels at once on one screen. There is also a function for viewing still images from different channels.

Picture tube parameters

When choosing diagonals for CRT TV you need to measure the distance from which you will watch TV, and divide by 5. This value will be the diagonal in centimeters (the distance is also in centimeters). With this size it will be comfortable to watch TV, you will not see the graininess of the picture and you do not need to strain your eyes to see small objects.

When choosing a 3x4 or 16x9 format you need to know what you are going to watch. If you watch a lot of DVDs, where films are widescreen, then you need to pay attention to the 16x9 format. If you are going to watch only terrestrial television, then choose 3x4 format.

Better choose a flat picture tube than convex. A flat picture tube has less distortion and a better picture, less glare from other light sources. But if you watch little TV (dacha, kitchen), then this is not so important. And yet, TVs with flat tube tubes are more expensive.

CRT TVs have good performance in terms of brightness, contrast and color rendition. According to these indicators, they are ahead of many LCD and plasma TVs and CRT TVs are second only to them in a set of functions and appearance. And expensive models with flat picture tubes also have many additional functions, which improve the picture and make it convenient to operate. And for the price, CRT TVs are cheaper than LCD TVs and plasma panels.

A movie on the big screen ... Probably little beats the viewing experience you get in a movie theater. But what if the rental of the work you are interested in has long ended and the film is presented only on DVD? Or you just don't feel like leaving the house? Well, there is always a solution - equip a cinema at home! It's not as difficult as it sounds. To do this, you need a DVD-player *, possibly a receiver, a multi-channel speaker system and, of course, a TV on which you will watch all this. The last component is probably the most important - it largely depends on it, whether you feel the full effect of presence, so clearly manifested in a dark cinema hall, or will perceive the film as an ordinary picture on the screen.

So what should you choose for your big screen? It can be a picture tube (CRT) TV, a projector, a projection TV, a plasma panel or a liquid crystal (LCD) TV that most of us are used to. What are the pros and cons of these solutions?

CRT TVs

Large CRT TVs are perhaps the most common component of low-cost home theaters. The technology, which is noticeably more than half a century old, allows the production of devices with a very affordable price. But the screen diagonal of most CRT TVs produced now does not exceed 34 inches, this is often not enough to fully feel like a participant in a cinematic action. The CRT is a rather bulky component, so be prepared for the TV to be about half a meter deep and weigh about 50 kg. (We are talking about mass models with a diagonal of 29-34 inches, TVs with a smaller screen size can hardly be classified as "cinematic".) The peculiarities of image formation lead to the fact that certain defects of the "picture" are often observed in the corners of the screen, such as -to: non-convergence of rays (the image consists of several colored elements, offset relative to each other), "blurring" (fuzzy, blurry image), geometric distortion (say, circles turn into ovals).

One more factor should be taken into account - CRT TVs are "living out" their days, they are being replaced by new display technologies. As a result, manufacturers focus on the price of the device, trying to keep it as low as possible, sacrificing other characteristics.

Multimedia projectors

An alternative to the usual TV can be a multimedia projector. A large screen is placed in front of the audience, and a small box - a projector - is installed in any convenient place, be it a shelf on the wall behind the back or a coffee table in front of the audience. Conveniently? Certainly! The screen, the diagonal of which can reach several meters (!), Can be moved to a new place at any time or even rolled up and removed. And the modest dimensions and weight of the projector allow you to forget about the problem of free space.

But the projectors also have significant drawbacks. The low brightness of the image on the screen forces to shade the room: during the day you have to draw up the blackout curtains, and in the evening - turn off the light. However, some people even like it - the atmosphere is like in a real cinema. A powerful lamp hidden in a miniature body requires intensive cooling, so all projectors are noisy to some extent. And if the noise is at an acceptable level for most models, then some specimens are very annoying. Considering that the projector itself is not far from the audience, this can seriously spoil the viewing experience.

By the way, about the lamp. Its service life is short and in normal mode ranges from one to three thousand hours (compare with ten to fifteen years of trouble-free operation for a CRT TV!). Eco-mode doubles the lamp life, but it comes at the price of reduced brightness. However, the drop in projector brightness is often noticeable after a couple of hundred hours of operation. Replacing the lamp is not difficult, but the price is a significant fraction of the cost of the projector itself.

Projection TVs

But what if we put the projector and the screen in one case, turning the structure into a kind of familiar TV? Such a "hybrid" turned out to be very successful from the consumer's point of view. The use of a projector instead of a kinescope made it possible to significantly reduce the depth of the case compared to CRT models, while maintaining a good image brightness, which makes it possible not to shade the room when viewing. Of course, in terms of maximum brightness and contrast (as, indeed, in thickness), projection TVs are inferior to plasma TVs, but with comparable diagonals they are much cheaper. Projection technology keeps the price down even on the 70-inch model.

True, projection TVs have retained the main disadvantage of conventional projectors - the relatively short service life and high cost of the lamp. But the problem of noise is no longer worth it: the large, by the standards of the projector, case made it possible to make the cooling system much quieter.

Plasma panels

Plasma panels can be called the first devices that made it possible to fully realize the idea of \u200b\u200ba home theater. A detailed story about this technology (as, indeed, about competing "liquid crystals") is ahead of us, now, to make the comparison look complete, we will briefly touch on the pros and cons of plasma panels. A large diagonal flat screen with excellent brightness and contrast provides a much richer picture than a traditional CRT TV. At the same time, the depth of the case for most models does not exceed 20 cm! Of course, the price of the first plasma TVs was “biting”, and even now it is difficult to call it low, but a high-quality image is expensive. Due to the technology of image formation, plasma panels have no non-convergence of rays and geometric distortions. Modern models delight with excellent color reproduction, close to the usual on CRT TVs (previously there were some problems with this).

But there are also disadvantages. First of all, this is the so-called memory effect. When a static image with bright areas is displayed, the phosphor of the panel cells burns out, and a ghostly trace of this “image” remains on the screen (an example is the logos of TV channels). Due to the technological features of "plasma" it is difficult to make a panel with a high resolution - at least it should have a solid diagonal. Although the viewer does not notice this, the plasma panel constantly flickers, which, when viewed at close range, causes visual fatigue. We'll have to come to terms with high power consumption and, as a result, some noise from the cooling system (fortunately, subtle in most models).

LCD TVs

But LCD TVs have appeared on the market relatively recently - liquid crystal technology was first honed on computer monitors. The diagonal of modern mass models is from 15 to 65 inches. And if the former can hardly be classified as "theatrical", then LCD TVs of large diagonals are a serious competitor to "plasma". Their advantage is the complete absence of flickering (you can install the screen closer to the viewer) and memory effect, on average, higher resolution (which is very important given the advent of high-definition television), lower weight and power consumption, lower price with a comparable diagonal. Naturally, there are no problems with the geometry of the image, with color misalignment.

Among the shortcomings, it is worth noting the lower contrast of LCD TVs compared to plasma panels, smaller viewing angles, some inertia of the LCD matrix (in dynamic scenes, the image looks slightly "blurry"). However, the last two problems are practically irrelevant for modern models. But the display of a low-resolution "picture" (TV broadcast or a signal from a DVD-player) by some LCD TVs still cannot be called ideal - not all manufacturers have managed to "teach" their models to scale the image with minimal loss of definition.

Nowadays, even a child knows what a TV is and uses it all the time. Technologies are constantly improving, CRT televisions are a thing of the past. They are being replaced by liquid crystal monitors, as well as LED technology.

Nevertheless, we will focus specifically on CRT televisions, because many continue to use them for certain reasons. They are also called CRT.

Device

If you come very close to a CRT TV, you will find that the picture on its screen consists of tiny dots. They flicker, burn brighter, or dim. If you move further away, what is happening on the screen is perceived as a moving picture. This is due to the ability of the human brain to collect everything into a single whole.

CRT screens are shaped like a pear. In place of the "handle" is a so-called electron gun, which directs the electronic streams to the screen. The surface of the screen is filled with phosphor dots. This is a substance that glows when an electric beam hits it. From these smallest points, a whole picture is formed on the screen of CRT TVs.

Where does the color come from?

The CRT screen is even more complex. On it, phosphors have different properties and glow green, blue and red. All other colors are obtained by mixing these three.

The electron beam rapidly shoots into the screen and affects the phosphor dots 25 times in an instant. As a result, the human eye sees a moving image. Electro-rays "run" over all lines on the screen in the shortest possible moments.

Specifications

CRT TVs differ in technical parameters:

• Screen size. The larger it is, the larger the TV itself. This means that the largest TV set will not fit in all rooms. If the dimensions of the room are modest, the technique must be chosen too small. The smallest TV has a diagonal of 10 inches. Popular are models with diagonals from 14-15 inches, as well as 20-25. The largest are 29 "and 34". When choosing a screen, you should determine in advance the location of the device in the room. A prerequisite is the presence of space between the body and the wall. Otherwise, the equipment will quickly fail.
• Screen format. Usually 4: 3 is used. 16: 9 wide picture is preferred for watching movies. The TVs also have auto-formatting.
• Scan, or rather its frequency, indicates the quality of the image. In previous models, it was 50 Hz, so the viewer had the feeling that the picture was constantly flickering. Later the frequency was increased to 100-120 Hz.
• Speakers. In small models, they are usually built-in, large-sized versions have stereo speakers.
• Connectors for connecting devices. Models that are being produced today are already equipped with more than just antenna connectors. As a rule, they have audio and video outputs to which you can connect video and DVD equipment.

Advantages and disadvantages

The advantages of CRT TVs are:

• affordable cost;
• variety of choice of models;
• excellent picture quality;
• realistic color;
• long service life.

The disadvantages of the technology include:

• large dimensions;
• negative effects on the organs of vision during prolonged viewing.

Image problems

Consider the most common malfunctions of CRT TVs:

• Screen image is blurred. This is due to a breakdown of the picture tube. The repairman can perform an additional winding on the transformer, but in the future it will be necessary to change the screen. If a bright glow with thin horizontal streaks appears on the screen, such a kinescope cannot be restored.
• The screen went blank. This occurs when a filament breaks or a short cathode is detected. With such a malfunction, the master checks for the presence of a circuit between the contacts. If there is no circuit, the screen cannot be restored. In another case, the master solders the contacts and fixes the breakdown.
• Image offset. In this case, the impact of rays on the phosphor is disturbed. You can try to knock on the edges with a rubber object, but most often you have to change the picture tube.

Typical defects of some models

There are also typical defects in some models. For example, in the Samsung CRT TVs, the power supply often burns out. The master changes the mains fuses. It is also possible that the image is disturbed due to a malfunction of the thermistor, it is changed to a new one.

If the TV suddenly smokes, you need to turn it off and urgently call the master. Usually the cause of the breakdown is swollen capacitors, which are replaced with serviceable ones.

Erisson TVs over time, they may not switch from standby mode to working state. This is due to the fact that the device activates the protection against burn-through of the kinescope if there is a breakdown in the vertical scanning units. Replacing a faulty transistor with a working one can help.

LG CRT TV is susceptible to other damage. Over time, it may not turn on. The master will inspect and check:

• are the capacitors in good working order;
• whether there are microcracks in the board and power circuit;
• if there was a detachment of contacts.

If any breakdowns are found, the master eliminates them, and the equipment pleases its owner with a working condition.

Of course, CRT TV repairs should be entrusted to professionals. In this case, you can be sure of the quality of the service, and the TV will last more than one year.

Briefly about the article: TVs based on CRTs and liquid crystals, plasma and projection - today we will consider all the known types of these "pets", because the TV not in the least depends on how pleasant it will be to watch your favorite films.

The story of the four "boxes"

Varieties of modern TVs

Not so long ago, the problem of choosing a TV for the majority of domestic consumers did not arise. Soviet industry produced two or three models for more than two hundred million people, and everyone was extremely happy. Today, hundreds of different TVs are dazzling in the eyes. Modern "boxes" differ not only in price and diagonal size, but also in the principle of the formation of the picture. Dark forest? So let's find clear guidelines in it.

One cannon - one screen

TVs based on picture tubes (CRTs - cathode ray tubes) appeared a long time ago, which is why they are the most common today. The principle of operation of such "boxes" is extremely simple. The reverse side of the screen is covered with a phosphor (when this substance is bombarded with charged particles, it starts to glow). An electron beam passes through it line by line, "setting fire" multi-colored phosphor dots.

The problem is that in one very short period of time only a few lines are lit on the screen. We see the whole picture only because of the peculiarities of our vision. The subconscious mind still "understands" such a deception, and we have to keep the components of the image in memory. That is, even while relaxing in front of such a TV, we strain a little.

CRT TV screens have been bulging for a long time. The engineers managed to get a "plain" instead of a "hill" ten years ago. Today, only the smallest and cheapest TVs are equipped with non-flat screens. By the way, the price is one of the most significant advantages of CRT models. Such TVs have now finally moved into the category of inexpensive solutions for people with a limited budget. This even applies to models of famous brands, including Sony , Philips and Panasonic .

Another advantage is that CRT technology is honed to the limit. Improving it is like reinventing the wheel or editing a classic novel. This means that almost all CRT TVs are equally good. The quality of the CRT picture is extremely satisfactory. The CRT is naturally endowed with fast response, good contrast and natural color. If you supplement the list of pros with an acceptable price and a long service life, it turns out to be a quite worthy candidate for a purchase.

CRT TVs also have disadvantages. Remember that the subconscious mind reveals the whole screen image deception? So, if you come close to the TV and look closely, your eyes will catch the flicker of the picture. Still, the turnover is not fast enough to go completely unnoticed. In part, this problem is solved by buying a high-quality TV with a 100 Hz vertical scan (fortunately, there are most of them now). The picture on it is updated 100 times per second, which noticeably reduces eye fatigue.

In addition, CRT images are prone to problems such as poor beam convergence (may show up in slight iridescence of objects), imperfect focusing (the picture loses clarity), and noticeable geometric distortion (a straight line looks curved).

We are so accustomed to the large size of TVs that we design the arrangement of furniture in the room taking into account the "hefty black TV box." But this is a disadvantage. Yes, the TV can be smaller and lighter, and in general it can be hung on the wall. But, of course, not a CRT. This is destined to live out its life "on the floor."

The conclusion on CRT TVs is the following: if you are constrained in budgetary funds (like our government), stop at the good old CRT "box". It will become a rare thing no earlier than in seven to eight years.

Picture from gas

A short physics lesson: plasma is the fourth state of matter (there is also liquid, solid and gaseous, if suddenly someone does not know). It is a fully or partially ionized gas, where the densities of positive and negative charges are approximately the same.

Why do we need to know this? For a better understanding of how plasma TVs work. After all, today they can increasingly be found on store shelves and in the living rooms of middle-income families. A plasma screen consists of two glass panels, between which are many tiny cells filled with an inert gas - neon or xenon. Each dot on the display is made up of three separate cells coated with red, green or blue phosphor.

Under the action of an electric current, the gas inside the pixels turns into plasma and begins to emit ultraviolet rays. UV radiation causes the phosphor to glow. The longer the cell is lit, the more brightness. In this case, the brightest points may not go out at all, and the dark ones simply do not light up. Image flicker is present, but not noticeable to our eyes.

The advantages of "plasma" are obvious: ideally flat screen of small thickness, huge diagonal (can reach two to three meters), bright and vivid colors, no problems with focusing and convergence of beams, relatively long service life, good viewing angles (when viewed from the side, colors are distorted insignificantly).

Meanwhile, the technology for producing "plasma" itself is very complex. Therefore, few people are engaged in the manufacture of such screens. Plasma TV manufacturers include the following: joint venture Fujitsu and Hitachi , NEC , Pioneer , Lg and Samsung ... All. Not a lot, right?

Well, now a few words about the very ones, without which it is impossible - the shortcomings. The first is that the price is too high. Many plasma TVs are no cheaper than a car. The second is high "voracity". A 42-inch panel requires at least 350 watts of power. CRT TVs are much more economical.

For those who like to pause the player in the middle of watching a movie and go about their business for a long time, "plasma" is not the best choice. Due to the peculiarities of the phosphor coating, when a static image is displayed for a long time, the intensity of the glow of individual pixels is noticeably reduced. That is, the brightness of the screen may decrease over time. In addition, due to the impressive weight (30-70 kg), it is rather difficult to hang a plasma TV on the wall. But you can. Otherwise, why is it so thin?

It is worth distinguishing between plasma panels and plasma TVs. And then, by paying several thousand conventional units, you can get a "TV", to which you can't even connect a TV cable. Yes, that's right: you need a TV tuner to receive plasma TV programs. If not, you will have to buy it separately.

There has been a lot of talk lately about high definition television ( HDTV - High Definition TV). This highest clarity is achieved through the large number of dots that form the image. So, modern plasma TVs for the most part have sufficient resolution (that is, the number of dots that form the picture) to display a new type of signal without distortion. However, they are well suited for modern television standards.

Liquid image

Liquid crystal display technology ( LCD - Liquid crystal display) has been around for several decades. The most natural LCD boom began in the late nineties of the last century and continues to this day. Today, more than half of computers are purchased with LCD monitors. Laptops have also been equipped with them for the last 15 years. The only thing left is to push CRT TVs out of living rooms.

Why are LCD TVs so good? Let's turn to the theory. The liquid crystal layer is sandwiched between two transparent panels made of film or very clean sodium-free glass. Under the influence of an electromagnetic field, the crystals change the axis of polarization of the light passing through them. As a result, one cell can change its value from the most transparent (white) to opaque (black). All intermediate values \u200b\u200bare shades of gray. To get a color image, it is enough to apply color filters to the cells. Thin-film transistors ( TFT - Thin Film Transistor), which are sprayed onto the screen in a special way. The number of thin film transistors can be in the millions. The process of creating an LCD screen is quite complex, so it should come as no surprise that LCD displays cost more than the most powerful computers in their early days.

The situation with LCD TVs is somewhat more complicated. They began to appear on the market relatively recently. Previously, the biggest problem was the impossibility of creating large LCD-screens - the largest ones barely reached 30 inches. But modern technology makes it possible to make screens up to 60 inches. On the other hand, one important advantage follows from this drawback. Not only large LCD TVs are produced, but also small ones with a diagonal of 15-17 inches. With plasma, this trick will not work. And there is no need to cover half of the wall in the kitchen with a TV screen. A slim and sleek LCD TV would be preferable.

LCD TV electronics constantly struggle to bring picture clarity to an acceptable level. The resolution of liquid crystal matrices is strictly fixed, since the number of cells cannot be decreased or increased. But the video signal often does not match the resolution of the TV. In this case, the image has to be scaled, which inevitably leads to the appearance of distortion.

In general, LCD TVs are gradually becoming "adults", and not only in size. The picture pleases every day more and more, approaching the ideal. The mass of such TVs is quite small: 24-inch models usually weigh no more than 13 kg. The power consumption is negligible. The price is almost always adequate.

And one warrior in the field

There is another type of televisions - projection televisions. Outwardly, they look like CRT, but the diagonal of their screen is usually much larger. A powerful lamp is hidden inside the body of such a "box", which projects an image onto a white screen. A large number of components are installed between the screen and the lamp, which form and improve the image.

Projection TVs are of two types. Some are based on cathode ray tubes, while others are based on liquid crystals. In the first case, three small picture tubes (for red, green and blue colors) are hidden inside the case, the rays of each of which travel a long way through a system of prisms, lenses and mirrors. The resulting image is projected onto the screen. Such TVs, like CRT models, have a disadvantage with the screen refresh rate: it can be either 50 Hz or 100 Hz.

Inside liquid crystal projection TVs, there is either one tri-color LCD matrix, or three (one each for red, green and blue). The formed image is illuminated by a lamp, then passes through a complex system of lenses and hits the screen. This type is preferable to the CRT version. Projection LCD TVs are lighter, have no geometry issues, and boast high definition (meaning high definition).

It is not uncommon for the backlight lamp to get very hot, so projection TVs are equipped with a cooling fan. So do not be surprised if you suddenly hear some kind of noise in the room - this TV is cooling.

* * *

"So what should you choose?" - you ask. The answer is simple: it all depends on the funds you have allocated for the purchase of a new TV. If you're running out of money, it's worth looking at a 100-Hz CRT TV. It will provide an acceptable picture quality and will last for more than a dozen years. The only "but" - large sizes can become a problem when installing such a "box".

Buying an LCD TV can be just as beneficial. The main advantages of this option are high image clarity, compactness and enviable lightness. Plasma and projection TVs make sense to buy if you want to get not just a big, but a huge screen. Today, a 50-inch projection TV costs less than an LCD of the same size. The same applies to plasma ones. But for the kitchen and bedroom, such giants are hardly suitable.