Evaluation of the thickness of the paintwork. Encyclopedia of radio electronics and electrical engineering

Encyclopedia of radio electronics and electrical engineering / Beginner radio amateur

 Comments on the article

This device is intended for an approximate determination of the thickness of the paintwork on ferrous metal products. It is suitable, for example, for detecting hidden damage on a car body. The coating thickness measurement range is 0,05 ... 1 mm, which makes it possible, when comparing two car parts, to verify the different thickness of the coating, which means to identify dents and damage repaired with putty or fiberglass, as well as to detect tinned areas of the body. In addition, the painting technology requires the application of various coatings, say, a primer, the thickness of which can be easily controlled by the proposed device.

The principle of operation of the device is simple (Fig. 1).

If the transformer, the magnetic core of which is assembled end-to-end, remove the closing plates, and instead bring the ferromagnetic material closer to the W-shaped plates, the voltage on the secondary winding will increase and become maximum when the material practically closes the plates. As it was established empirically, the highest sensitivity of such a sensor lies within the above limits, provided that a voltage with a frequency of 30 ... 50 Hz is supplied to the primary winding.

The device is powered from the AC network through a step-down transformer T1 (Fig. 2).

The power indicator is the HL1 LED, the current through which is limited by the resistor R1. The voltage from the secondary winding of the transformer is supplied through resistors R2, R3 to the primary winding of the transformer T2 - the sensor of the device. From the secondary winding, the voltage is supplied to the rectifier, made on the VD1 diode. Depending on the thickness of the paintwork, the value of the rectified voltage will change. The thickness is determined by the deviation of the pointer of the PA1 indicator. It is set to a conditional reference zero by a variable resistor R3.

Transformer T1 - any small-sized, with a power of about 5 W with a voltage on the secondary winding of 10 ... 12 V, LED - any of the AL307 series, diode - D9 series or low-power rectifier, resistors and capacitors - of any type, pointer indicator - with full current arrow deflection 50 μA.

Transformer T2 is self-made, it is performed on a magnetic circuit Ш 12x14, winding I contains 200, and II - 2000 turns of wire PEV-1 0,12. When assembling the magnetic circuit, the closing plates are not installed. Together with the capacitors and the diode, the transformer is placed in a plastic case of suitable dimensions (Fig. 3), which, after preliminary adjustment, is filled with epoxy glue. When the glue hardens, the working surface of the sensor is cleaned with sandpaper until a smooth surface is obtained. The remaining parts are fixed in another plastic case, and a calibration metal plate made of magnetically soft material is placed on its rear wall.

Setting up the device before pouring into the case is reduced to the selection of capacitor C1 to obtain maximum sensitivity - the largest difference in the indicator readings, when the calibration plate is pressed against the sensor and removed. Next, a resistor R2 is selected of such resistance that, with the plate pressed and the trimming resistor's engine approximately in the middle position, the indicator needle deviates to the final division of the scale - zero reading.

It is convenient to calibrate the device with the help of banknotes inserted between the sensor and the plate. Knowing the thickness of the new banknote (0,1 mm), it is easy to put the thickness values ​​on the indicator scale or make a calibration table. It should be noted that the scale of the device is uneven, and in the absence of metal near the sensor, the indicator needle deviates by about a fifth of the scale.

Author: A.Velsky

See other articles Section Beginner radio amateur.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Alcohol content of warm beer 07.05.2024

Beer, as one of the most common alcoholic drinks, has its own unique taste, which can change depending on the temperature of consumption. A new study by an international team of scientists has found that beer temperature has a significant impact on the perception of alcoholic taste. The study, led by materials scientist Lei Jiang, found that at different temperatures, ethanol and water molecules form different types of clusters, which affects the perception of alcoholic taste. At low temperatures, more pyramid-like clusters form, which reduces the pungency of the "ethanol" taste and makes the drink taste less alcoholic. On the contrary, as the temperature increases, the clusters become more chain-like, resulting in a more pronounced alcoholic taste. This explains why the taste of some alcoholic drinks, such as baijiu, can change depending on temperature. The data obtained opens up new prospects for beverage manufacturers, ... >>

Major risk factor for gambling addiction 07.05.2024

Computer games are becoming an increasingly popular form of entertainment among teenagers, but the associated risk of gaming addiction remains a significant problem. American scientists conducted a study to determine the main factors contributing to this addiction and offer recommendations for its prevention. Over the course of six years, 385 teenagers were followed to find out what factors may predispose them to gambling addiction. The results showed that 90% of study participants were not at risk of addiction, while 10% became gambling addicts. It turned out that the key factor in the onset of gambling addiction is a low level of prosocial behavior. Teenagers with a low level of prosocial behavior do not show interest in the help and support of others, which can lead to a loss of contact with the real world and a deepening dependence on virtual reality offered by computer games. Based on these results, scientists ... >>

Traffic noise delays the growth of chicks 06.05.2024

The sounds that surround us in modern cities are becoming increasingly piercing. However, few people think about how this noise affects the animal world, especially such delicate creatures as chicks that have not yet hatched from their eggs. Recent research is shedding light on this issue, indicating serious consequences for their development and survival. Scientists have found that exposure of zebra diamondback chicks to traffic noise can cause serious disruption to their development. Experiments have shown that noise pollution can significantly delay their hatching, and those chicks that do emerge face a number of health-promoting problems. The researchers also found that the negative effects of noise pollution extend into the adult birds. Reduced chances of reproduction and decreased fertility indicate the long-term effects that traffic noise has on wildlife. The study results highlight the need ... >>

Random news from the Archive Photosynthesis for energy production 04.09.2018 Biologists have found a new way to use solar energy for good purposes. By changing the mechanism of photosynthesis in plants, they learned how to split water into hydrogen and oxygen, releasing energy in the process. Photosynthesis is the process of "converting" sunlight into energy that plants use. Oxygen is its by-product, formed as a result of the decomposition of water absorbed by the plant. Perhaps photosynthesis is the most important reaction for all life on Earth, as it produces almost all the oxygen in the planet's atmosphere. Hydrogen, which is also formed during the splitting of water during photosynthesis, has the potential to be an environmentally friendly and inexhaustible source of energy. A team of researchers led by academics from St John's College at the University of Cambridge used sunlight to split water into hydrogen and oxygen during a process of artificial photosynthesis, which the scientists tweaked with biological components and new technologies. With this method, plants absorb more sunlight than usual. "Natural photosynthesis is inefficient, as it was developed solely for the survival of plants, so it provides the minimum required energy - only 1-2% of what it can potentially give out," commented Katarzyna Sokol, one of the authors of the work. Artificial photosynthesis has been around for decades, but it has never been successfully used to create renewable energy because it relies on expensive and toxic catalysts. For the same reason, no one has tried to use it at the industrial level.

Other interesting news:

▪ External battery for Sanho HyperMac laptops

▪ Exercise bike with built-in power generator

▪ Service for shared rides on self-driving vehicles

▪ Samsung continues to support Rambus

▪ High end mobile phone V80 from Motorola

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the Electrician website. Article selection

▪ article Two camps is not a fighter, but only a random guest. Popular expression

▪ article How did cooking begin? Detailed answer

▪ article Gachny knot with a hose. Travel Tips

▪ article Microfaradometer. Encyclopedia of radio electronics and electrical engineering

▪ article The cards held by the spectators are reversed. Focus Secret

Leave your comment on this article:

All languages ​​of this page

Arabic	Hebrew	Polish
Bengali	Hindi	Portuguese
Chinese	Italian	Spanish
English	Japanese	Turkish
French	Korean	Ukrainian
German	Malay	Vietnamese

Home page | Library | Articles | Website map | Site Reviews

www.diagram.com.ua
2000-2024