JuliaCao's blog

The tuner is a very small part of the guitar, and few people even pay special attention to it, but it is the most basic part of the guitar.

The quality of the string buttons has a great impact on the intonation. If the tuner is not good enough, it will be difficult to adjust it just right. If it is too high, it will be high, if it is too low, it will be low. If it is too high, you will want to turn around but find that it is spinning again. This is especially true for poor-quality tune buttons. They either loosen when touched, or loosen and tighten when turned. Some of them are tight or cannot turn even if strings are not installed. The new strings are not tuned just after they are installed. It breaks after a few clicks, and the usual culprit is basically this kind of inferior tune button. And good tuners, even when using a capo, rotate very smoothly and the pitch is very accurate. A good set of guitar tuners can greatly improve the performance of your guitar. The tuners that come with many guitars from the factory are of average quality, so it is necessary to choose good tuners.

But before you confirm your purchase, you must first confirm that you have selected a suitable tuner product. There are various tuners on the market with different qualities, so you need to understand the tuners of various qualities and have a good reputation.

Players who love guitar will have heard of the GOTOH brand. Taylor/Martin's high-end guitars all use GOTOH tuners. The 510 series is GOTOH's star product that reflects its strength. Whether it is the buttons or the bridge, when you see the 510, you will know that it is a cutting-edge product. The piano buttons of the SG510 series are classics among GOTOH products. Its sleek and streamlined appearance can be said to be familiar to almost everyone. Everyone who has used it is impressed by its even damping of rotation.

GOTOH's locking tuners can better prevent the problem of string running. The locking device on the tuners prevents the strings from slipping, and you don't have to wrap the strings around the tuner posts multiple times.

If you want to upgrade your guitar to have a better appearance and more accurate intonation, you might as well try GOTOH's knobs, I believe you won't be disappointed.

In today's society, electric energy has become the cornerstone of the development of all walks of life, and high-current plugs and sockets are the key carriers to carry and transmit this energy. They are like solid bridges, transporting powerful current safely and stably to various electrical equipment, supporting the normal operation of modern life.

High-current plugs and sockets are mainly used to carry the power input and output of larger power equipment, such as industrial production equipment, data center server clusters, electric vehicle charging piles, etc. This type of plug and socket is well designed and uses high-quality copper alloy material as the conductive component. It has the characteristics of low resistance and high current carrying capacity. It can withstand the working pressure under long-term high current load and effectively avoid accidents caused by excessive current. heating phenomenon to ensure the stable operation of the power system.

Taking the new energy vehicle industry as an example, the rapidly developing electric vehicle industry has put forward higher requirements for charging facilities, and high-current plugs and sockets play an indispensable role here. During the DC fast charging process of electric vehicles, high-current plugs and sockets can carry hundreds of amps of high current, enabling rapid replenishment of electric energy in a short time. At the same time, they have multiple built-in safety protection mechanisms, such as overload protection, short-circuit protection, and anti-electric shock design. etc., which can ensure the safety and reliability of the entire charging process.

Another example is that in large-scale data centers, each server requires a stable power supply. At this time, high-current plugs and sockets can meet the needs of high-density and high-power power supply. Through a series of accurately matched electrical connection solutions, ensure The data center operates continuously, reducing the risk of data loss or system crash due to power problems.

Generally speaking, high-current plugs and sockets have become a vital part of modern power systems due to their excellent performance and strict safety standards. In the future, with the emergence of more high-energy-consuming and high-power equipment, high-current plugs and sockets will continue to shoulder the important task of safely and efficiently transmitting large currents while continuously improving their quality and performance, contributing to the sustainable development of the economy and society. Provide strong power support.

I have been engaged in decoration recently, and I have been studying for a long time with colleagues who are also engaged in decoration. For us, smart switches control lights + smart home appliances are enough, so I integrated various online tutorials and wrote this article using my own house as an example for your reference.

This article mainly talks about the layout of smart switches. Smart home appliances are very simple. Now home appliances can basically be connected to each other. Otherwise, you can also buy a smart socket to control. Just remember to leave a socket for electric curtains and other things.

1. Basic principles of smart switches

Principle: dual control to single control + wireless switch!

Mechanical switches are dual-control: For example, my master bedroom is dual-control according to the traditional wiring method. The main light in the master bedroom has a switch at the entrance and at the bedside.

The smart switch is a single control: install the smart switch, cancel the wire from the main light to the bedside switch + cancel the bedside mechanical switch + leave a neutral wire for the door switch, install a smart switch at the door, and place a wireless switch at the bedside.

2. A bit more complicated

According to the traditional method, in the public area, the decoration company arranged for me to have dual controls for the entrance downlights and the main lights in the living room, and single controls for the others.

According to the basic principle, I want to do two things:

1. Change the dual-control entry downlights and living room main lights to single-control.

2. Simplify the distribution of switch panels and gather the lights in the living room and dining room together. So I put all the five light switches in the living room, dining room, and shoe cabinet in one place opposite the shoe cabinet, arranged two smart switches with 3 buttons and 2 buttons, and bought a wireless switch. The smart switches for balcony lights and entry downlights are still placed near the lights.

In this case, just buy two single-button, one double-button, and one three-button smart switch + 1 wireless switch.

3. Regional distribution

Not every switch panel is smart. I personally think it would be simpler to realize smartness in areas with more lights and switches. Some simple single-control areas do not need to be smart, such as kitchens and toilets. This depends on personal needs.

Some of the lights in the entrance, dining room, living room, balcony, multi-functional room, and master bedroom are smart switches. The kitchen, public bathroom dry area and wet area, parent room, master bedroom bedside chandelier, and master bedroom bathroom are ordinary mechanical switches.

Purchase smart switches for the whole house: 4 single buttons, 2 double buttons, and 1 triple button.

Question 1: Is it possible to retain the dual control circuit and the switch is an intelligent switch + a mechanical switch?

Answer: No, you cannot have smart switches and mechanical switches on the same line at the same time. The smart switch needs to be connected to the neutral wire and live wire for power supply, and the mechanical switch will cause the smart switch to lose power.

Question 2: How to reserve the neutral line?

Answer: For a device to be energized, it needs neutral wire + live wire for power supply. The lamp is connected to the neutral wire, and the mechanical switch is connected to the live wire. If the blank is simpler, you can directly pull a neutral wire from the switch. If it is hardcover, it will be complicated. It depends on the actual situation. You can connect the neutral wire from lights, sockets, etc. to the switch.

Cars are the most common means of transportation in our daily lives. With the development of our country's economy and the general improvement of people's living standards, cars have become an affordable means of transportation for most families. The comfort, speed and safety of automobiles have become an indispensable means of transportation in modern life. Therefore, the automobile market is huge and developing very rapidly. This year, we discussed the relevant knowledge of connectors in automotive wiring harnesses. Many people know that there are hundreds of optical connectors in a car. So do you know how to distinguish the types of automotive connectors? The following introduces you to the specific classification of automobile connectors. Generally speaking, the types of automotive connectors can be divided into six aspects: function, installation position, connection structure, shape specifications, size specifications, shape specifications, and operating frequency.

1. Electrical functions: electronic control module (on-board computer), lamp holder, temperature sensor, central electrical box, air conditioning wiring harness, audio entertainment

2. Classified by installation location: chassis system, instrument system, engine system, safety system

3. According to the connection structure of line-line-board-board, flexible circuit board FPC, chip package (IC pin type)

4. Dimensions: rectangular, round

5. According to shape specifications: round tube (ordinary, coaxial), rectangular tube (sealed, non-sealed)

6. Classification by operating frequency: low frequency and high frequency (limited to 3 MHz). For other classification methods, automotive connectors can still be classified according to use, special structure, installation method, special performance, etc., but generally just to highlight certain Characteristics and uses, the basic classification still does not exceed the above classification principles.

Combined with the technological development and actual situation of automotive connectors, let me introduce to you other categories of automotive connectors: ① low-frequency circular connectors; ② rectangular connectors; ③ printed circuit connectors; ④ optical fiber connectors; ⑤ radio frequency connections device. There are some terms that sound familiar to you, but you have rarely seen them, such as chassis system, instrument panel, engine system, temperature sensor, etc. The realization of these important functions is incomparable to automotive electronic connectors. The above are the types of automotive connectors that I will introduce to you today. Through the above explanation, do you have a clear understanding of the types of automotive connectors?

With the general improvement of people's living standards, cars are no longer a "luxury" that wealthy people can afford, and they have entered thousands of households. The demand for automobiles in terms of safety, comfort, environmental protection, and intelligence is growing day by day. The applications of automobile electronic products such as car audio, GPS navigation, entertainment equipment, airbags, automobile optical fiber networks, ABS systems, etc. are also increasing. As car interiors become more complex, more car connectors are needed. It is expected that the number of automotive electronic connectors will reach 600 to 1,000 per vehicle in the future, and the types of automotive connectors may also change. The automotive connector market will become larger and larger in the future, and its development prospects are also worth looking forward to.

In today's rapidly developing manufacturing industry, multi-row packaging machines, as key equipment on the production line, play a vital role. It can not only greatly improve production efficiency, but also ensure the consistency and quality of product packaging. However, like all efficient mechanical equipment, multi-row packaging machines also require regular maintenance to ensure their long-term stable operation. This article will delve into the importance of preventive maintenance and how to implement this strategy to ensure the long-term stability of multi-row packaging machines. Long-term stable operation.

The importance of preventive maintenance

Preventive maintenance is a proactive maintenance strategy that aims to prevent failures from occurring by regularly inspecting and maintaining equipment, rather than taking action only after equipment problems occur. This approach is particularly important for multi-row packaging machines because :

(1) Improve production efficiency: By reducing sudden shutdown events, preventive maintenance can help keep the production line running continuously, thereby improving overall production efficiency.

(2) Extend equipment life: Regular maintenance can reduce equipment wear and extend its service life, thereby reducing long-term capital expenditures.

(3) Reduce maintenance costs: Compared with repairing major faults, regular preventive maintenance is usually less expensive and can significantly reduce overall maintenance costs.

(4) Ensure product quality: The good operating status of the equipment can ensure the consistency of the packaging process, thereby ensuring product quality.

Multi-row packaging machine

Implement a strategy for preventive maintenance

(1) Regular inspection and records: Establish a plan to regularly inspect various components of the multi-row packaging machine, including but not limited to motors, transmission belts, sensors, etc., and record the inspection results. This helps track the wear and tear of the equipment and detect potential potential problems in a timely manner. question.

(2) Cleaning and lubrication: Keeping equipment clean and well-lubricated is the basis of preventive maintenance. Dust and dirt may cause equipment to overheat or component wear, while proper lubrication can reduce friction and prevent premature damage to components. Operation Operators should regularly clean the dust and dirt on the surface of the equipment and use appropriate cleaning agents for cleaning. Pay special attention to cleaning the sealing parts and the transmission system to ensure that they are dust-free and free of impurities. And select appropriate lubricants and follow the prescribed intervals. and methods for lubrication. At the same time, pay attention to the amount of lubricant used. Too much or too little will have a negative impact on the operation of the equipment.

(3) Parts replacement: For easily worn parts, such as sealing rings, cutters, etc., they should be replaced regularly according to the equipment usage time or usage conditions to avoid failures caused by component aging.

(4) Check the electrical system: Regular inspection of the electrical system of the multi-row packaging machine is an important part of maintaining the safe operation of the equipment. The operator should check the connection and fixation of electrical equipment such as power cords, sockets, switches, etc. to ensure their normal operation. At the same time , it is also necessary to check the working status of various electrical components, such as sensors, motors, etc., and repair or replace them in time if any problems are found.

The international freight forwarding industry in China began in the 1990s. The first link in the system was the logistics department of international trade companies. In the early days, it was mainly responsible for customs declaration business. Later, it gradually expanded to include towing, customs declaration, sea transportation, and air transportation. , transnational road transportation and railway transportation business. Due to the continuous expansion of business scope, many international trading companies have separated out this work and outsourced it to relatively mature international logistics companies. This is now the international freight forwarding, whose full name is International freight forwarding company.

The main business of international freight forwarding

The main business contents of international freight forwarding are as follows:

1. Accepting inquiries from customers (the main business of international freight forwarding)

Air freight inquiry

① The customer needs to provide the departure airport, the destination airport, the specific information of the goods (product name, weight, number of square meters, number of pieces, size of large items, etc.), the specific or expected time of the customer's delivery, and whether there are formal export documents , is it a direct flight or can I accept transfers, are there any time limit requirements, are there any restrictions on airlines, etc.

② Make a quotation based on the information provided by the customer, and inform you of flight information and air transportation precautions.

2. Shipping inquiry

① The customer needs to provide the port of departure, port of destination, specific information of the goods (product name, weight, bulk or container cargo, etc.), bulk or container cargo, what type of container the container is, timeliness requirements, whether the shipowner has any preference, and normal customs declaration Or pay the bill and wait.

② Make quotations based on the information provided by customers, and inform shipping schedule information and shipping precautions.

3. Land transportation inquiry

① Customers need to provide the place of departure and destination. Land transportation generally involves double clearance, that is, customs declaration and clearance at the port of departure and port of destination, specific information about the goods, timeliness requirements, normal customs declaration or paid customs declaration, etc.

② Make a quotation based on the information provided by the customer, and inform the customer of timeliness information and road transportation precautions.

4.International Express Inquiry

①Customers need to provide the shipping address, destination address, specific information about the goods, whether the express company has any requirements, timeliness requirements, customs declaration details, etc.

② Make a quotation based on the information provided by the customer, and provide timeliness information and express delivery precautions.

5. Railway transportation, sea-truck intermodal transport, rail-truck intermodal transport, etc.

The content is roughly the same as above.

2. Order taking (the main business of international freight forwarding)

①The customer accepts the quotation and agrees to place the order

② When the customer places a BOOKING confirmation, the general content of BOOKING is as follows:

The content includes: specific shipping date, product name, number of pieces, weight, volume, consignee information, etc.

The main business of international freight forwarding

3. Booking (the main business of international freight forwarding)

According to the content of BOOKING, apply for booking from shipowners, airlines, railway transportation companies, etc.

Get a delivery note.

4. Boxing or receiving (the main business of international freight forwarding)

According to the customer's needs, arrange a trailer or truck to collect the goods at the door, or let the customer send the goods to a designated address for collection. Domestic operations can be operated in stages. Some only require booking of space, and the customer returns the goods to the designated terminal, airport or Warehouses are enough, and some are fully operational.

5. Arrange customs declaration (the main business of international freight forwarding)

Regardless of any international logistics method, it involves customs declaration. Customers can make customs declarations by themselves, and international freight forwarders can declare customs on their behalf. Customs declaration methods can be divided into normal customs declaration and paid customs declaration. Normal customs declaration means that the customer provides customs declaration documents for customs declaration. Paying customs declaration requires an international freight forwarder to provide a third-party document header for customs declaration.

6. Bill of lading (the main business of international freight forwarding)

After customs declaration and release, wait for the shipowner or airline to issue the bill of lading. After the bill of lading is issued, you can charge the customer the fees and then give the customer a telex release (referring to the electronically authorized bill of lading) or provide the original bill of lading. In case of double clearing, there is usually no bill of lading, just For payment, after the goods arrive at the port, the international freight forwarder notifies the agent at the destination port to deliver the goods to your door. As for express payment terms, payment is usually made after receiving the express delivery and checking the express delivery track on the official website of the international express company. A rough sample of the bill of lading is as follows:

The main business of international freight forwarding

6. Providing export document services (the main business of international freight forwarding)

It involves documents required for export, such as CO (certificate of origin), FA, FE, export documents, commodity inspection, etc. Some documents are required for customs clearance at the port of destination, and some are required by the port of departure. If the customer cannot handle these documents by themselves , you can ask international freight forwarders for help.

7. Warehouse and other international supporting services (the main business of international freight forwarding)

When customers have loading and unloading requirements, international freight forwarders need to provide warehouse warehousing and loading and unloading, including domestic warehouses and international overseas warehouses, as well as some specific supporting services, such as providing freight insurance, inspection of foreign trade goods, and other related supporting services. .

The above is the main work content of international freight forwarding.

Economical and affordable: The price of diesel engines is lower than gasoline engines of the same power, so it can reduce the cost of power generation.

Reliable and stable operation: Diesel engines have less impact on the climate and have lower failure rates, making their operation more reliable and stable.

Low noise: The noise generated by the diesel engine during operation is low, generally below 80 decibels, which is much lower than that of gasoline generator sets.

Low maintenance costs: Diesel engines have longer maintenance intervals and smaller oil consumption, making their maintenance costs lower.

Long service life: The diesel engine can be used continuously for more than 100,000 hours, reducing the trouble of replacing equipment.

Low fuel costs: Diesel engines have lower fuel consumption, and each unit saves about 0.4 yuan in fuel consumption per hour on average compared to a turbine-generator unit.

Strong environmental adaptability: It can be used in cold or hot environments, high altitudes or mines.

The disadvantage is that the better the brand and the higher the quality of the unit, the price may be higher. Burning diesel will cause certain air pollution. Of course, this problem will occur whether it is gasoline or diesel.

The European Cup is going on in a lively manner. You watch the football stars dribbling, passing and shooting one by one. It's like they have magical powers on the soles of their feet, rubbing against each other on the green stage. However, football and lawn are not related at the beginning. It doesn’t matter if you don’t play well. You can first understand this magical “green”.

Croatia star Modric skates and kneels on the lawn

From dust to grass The lawn became a venue for football matches only in the 1960s. Before that, it was held on dirt grounds - football was dusty on sunny days, but when it rained, it turned into a mud pond. game. Turf just solves these problems. In addition, football is becoming more and more popular. With many professional players making a living and large-scale competitions, the competition has become more intense and there are more and more physical confrontations between players. Turf is also popular among players because it has good elasticity and can cushion the impact when falling.

The lawn of the football field is naturally not as disorderly as the meadows where horses are grazing, nor is it like the green grass in the park, which is just a "face project." Because people have to exercise vigorously on it, they have special requirements for its elasticity and hardness. Therefore, the lawn of football fields is very particular. Over the past decades, a complete set of systematic projects has gradually been formed.

The first is the selection and combination of grass species. Next, we need to consider the physical structure of the lawn, with clear layers such as drainage layer, support layer, buffer layer, etc. Later, floor turf and artificial turf emerged that could be disassembled and assembled. With every World Cup, team players are updated and the stadium lawns also keep pace with the times.

The structure of a football field lawn is no simpler than a building. Its underground part is divided into 4 floors:

1--Sand layer: It is composed of soil and fine sand. It is the planting layer and nutrient layer of lawn grass, which can fix the grass roots and retain fertilizer. At the same time, the soft sand can also cushion the impact of falling or sudden stops and turns during exercise.

2--Mixed layer of gravel and coarse sand: Larger particles of gravel and coarse sand can prevent the upper layer of fine sand from falling into the water pipes and blocking the water pipes, but at the same time it does not delay water seepage.

3--Pebble layer: Select large pebbles to cover the pipe network, which can support the upper soil and does not affect water seepage.

4--Drainage pipe layer: Drainage pipes are the channels for the circulation of excess water in rainy and snowy weather or after watering. It is in the shape of an inverted trapezoid with an open top and is embedded in rammed earth. The entire network of drainage pipes is arranged in a fishbone shape.

Therefore, there is a big difference between the lawn of a football field and the lawn in the park or on the hill behind your house.

The grass of the stadium lawn cannot be scrawled. Not all grass is suitable for football field lawns. The most basic standard is that it must have strong viability, be resistant to trampling, and be easy to take care of. If a game had not been played, the lawn would have been devastated. Most lawn grasses are selected from wild grasses through artificial cultivation. Their common characteristics are: many and small leaves, slender and upright, and tough leaf sheaths. The densely grown small leaves make the lawn very dense; the upright and slender grass blades help light transmit to the lower layer of the lawn to prevent the plants from growing poorly due to being too dense; the tough leaf sheaths can protect the leaves during pruning and trampling.

The seasons of the five major football leagues such as the Premier League and Serie A, which are popular around the world, span almost 10 months of the year. Therefore, in order to maintain green grass for a long time, most football fields choose grass species with a leaf green period of more than 200 days. Geographically speaking, each football field is located at different latitudes, with different cold, warm, dry and wet conditions. The selection of turf grass will also be based on local conditions - usually the 35° latitude line is used as the boundary, and cold and warm turf grass are planted respectively.

cool season turfgrass

The genus Poa in the family Poaceae is distributed in temperate and sub-arctic zones, with approximately 250 species worldwide. It can successfully survive the winter at a low temperature of -20°C and remains green at -9°C, but has poor heat resistance and begins to wither when the temperature reaches 25°C.

Ryegrass belongs to the genus Lolium in the family Poaceae, mainly distributed in the temperate continent of Asia and Europe, with more than 10 species in total. It can still grow during the long winter, but is dormant in summer.

Tall fescue belongs to the genus Festuca of the family Poaceae and is distributed in temperate and subtropical regions. It is the most resistant to drought and trampling among all lawn grasses, can adapt to extensive maintenance, and has strong disease resistance, but it is not tolerant to high temperatures.

In areas with latitudes higher than 35°, football fields are mainly planted with cool-season turfgrasses such as bluegrass and ryegrass. They are short in stature, have thick leaves, and are resistant to poor soil and severe cold. In places with latitudes below 35°, warm-season lawn grasses are mainly sown. As you can tell from their names, they come from the tropics: Manila grass, Bermuda grass... Most of them reproduce quickly, have a long lifespan, and will not wilt when exposed to the sun. Warm season turfgrass

Manila grass, a genus of Zoysia in the Poaceae family, is distributed in tropical and subtropical regions of Asia and Australia.

It has excellent toughness and elasticity and is extremely resistant to trampling. Manila grass likes to grow in hot and humid environments and reproduces quickly.

The Bermudagrass genus Bermudagrass is distributed in the tropical regions of southern North America.

The suitable growth temperature of Bermuda grass is between 25 and 35°C. It likes a humid environment and stops growing when the temperature is lower than 16°C.

Paradise grass belongs to the genus Paradise grass in the family Poaceae and is distributed in subtropical areas of Asia and Africa. The plant is low-growing and has dense leaves, making it particularly suitable for football field lawns. It has a well-developed root system and outstanding drought tolerance.

Painting on the lawn is not just for good looks

Stade de France, one of the venues for the European Cup

Some people may ask that stripes, concentric circles or grid patterns are often seen on football field lawns, and the colors are different, deep and light. Is it just for good looks? In fact, in addition to having a decorative and beautiful effect, these patterns can also help players, referees and spectators judge whether it is offside. According to different "drawing" methods, it can also be divided into temporary patterns and permanent patterns.

temporary pattern

It is a pattern pressed into the lawn with a roller. When mowing the lawn, use a roller to roll it in different directions so that the stems and leaves of the lawn grass fall in different directions. Due to the difference in light reflected from the leaf surface, the lawn shows dark and light patterns. But after a period of growth, the lawn grass returns to its natural vertical state, and the pattern will disappear.

The lawn can also be made into a checkerboard pattern. The picture is of the Toulouse Municipal Stadium for this European Cup.

permanent pattern

It is formed by planting lawn grasses with different leaf colors. Before sowing, first draw a pattern on the base soil layer, and then sow seeds according to the pattern. The color differences between varieties are used to express the pattern.

Why do items packaged in vacuum bags become moldy? The vacuum bag is a kind of vacuum bag that prevents air from entering. Microorganisms and bacteria cannot survive in the bag. It can greatly increase the shelf life of the food in the bag and greatly extend the storage time of the food.

Generally, vacuum bags can be divided into two types of materials: one is a vacuum bag made of transparent material, and the other is a vacuum bag made of aluminum foil. The price and advantages of each material are different, and they all have their own advantages. The conventional thickness of vacuum bags can be divided into eight wires and eighteen wires. Sometimes thicker is not always better. It depends on the products you are loading. Of course, for sharp objects, thicker is always better. Some products may become moldy in their packaging bags. What causes this?

Mildew of goods in vacuum bags is mostly caused by the following reasons:

1. The packaging material has low thermal insulation - carbon dioxide and methane in the natural environment are transferred into the carton through the packaging bag, causing residual bacteria to inhabit and mate, especially at low temperatures. This is especially true in low-temperature natural environments.

The second is that the packaging material has low mixing fastness - the composite film used in the packaging bag has low peeling strength between single-layer films, that is, the mixing fastness between single-layer films in the composite film is low, making it difficult for mixed cell membranes to peel off. The layer effect results in an increase in the overall performance of the composite membrane, such as positive resistance.

The third is that the raw material carton manufacturing process has little air tightness - the packaging bag body has little air tightness or heat sealability. When the raw material carton is placed for a long time, it is difficult for the raw material carton to leak slowly.

Fourth, the disinfection is incomplete-that is to say, some bacteria remain in the raw material cartons. These bacteria will inhabit and mate in large numbers when encountering an environment with suitable concentration, temperature or concentration.

We have a few suggestions for overcoming problems:

1. Pay attention to the oxygen permeability, water vapor permeability, container efficiency (negative pressure method), heat sealing wind speed, and peel strength of the packaging material.

2. Select materials with low barrier efficiency and poor mixing fastness or increase the volume of original packaging materials.

3. It improves the sterilization performance and increases the sealing volume of  heat sealing.

Common output anomalies

Power supply is an essential core component of electrical equipment. We usually hope that it is stable, reliable, high-precision, and high-performance. We can check these indicators from its technical manual. However, when we test in the laboratory or in actual applications, we often find that the test parameters do not match the nominal parameters. Usually there are the following situations:

1. The output voltage is low or high;

2. The output ripple noise exceeds the specification;

3. There is no output after working continuously for a period of time;

When we encounter these problems, how should we analyze, confirm and eliminate the problems? Next we will analyze the problems one by one

1. The output voltage is low or high

Usually, there are two reasons why the output voltage is low or high:

1) Accidentally touching the adjustable resistor:

Judgment method: Use a multimeter to directly measure the output terminal voltage to determine whether it is the standard output voltage;

Solution: You can rotate the adjustable resistor according to the direction on the label to appropriately increase the output voltage to meet actual needs;

2) The distance between the customer load and the power supply is too long, and the output line loss is too large.

Judgment method: test and compare the voltage at the output terminal of the power supply and the voltage at the input terminal of the customer's load;

Solution: It is recommended to shorten and thicken the wiring between the power supply and the load;

2. The output ripple noise exceeds the specification.

Typically, there are three reasons why output ripple noise is out of specification:

1) The ground loop introduces high-frequency signal interference, and the oscilloscope bandwidth setting is large

Judgment method: Check whether the method of testing ripple noise complies with the recommended method and wiring method in the technical manual;

Solution: Use correct testing methods. Inappropriate testing methods will cause test distortion, lead to misjudgment of results and other problems. Usually during ripple and noise testing we will limit the bandwidth, which mainly depends on the operating frequency range of the module under test. Take the power module as an example. Usually the operating frequency of the power module is below 500KHz, and the frequency of switching noise is also mostly below 5MHz. Therefore, during the test process, it is recommended to limit the bandwidth to 20MHz, so as to ensure that the tested is the ripple noise generated by the real power supply. At the same time, in order to avoid interference on the ground line of the oscilloscope's power supply during testing, it is recommended to cut off the ground pins on the oscilloscope's power line.

        Conventional testing methods are parallel line testing method and dependent testing method. The parallel line testing method is as follows:

Capacitor C1 in the figure is a ceramic capacitor; C2 is an electrolytic capacitor. The default values of C1 and C2 are 1uF and 10 uF respectively;

The test method is as follows:

Compared with the conventional wire-splitting test, the lean-to test method mainly reduces the area of the ground loop to avoid coupling interference in the ground loop during the test, which affects the test results. The main method is to remove the ground clamp as shown in the picture and directly use the copper ring on the probe as the ground. This can effectively avoid the impact of the external electromagnetic environment on the test.

2) The N line of the isolated power module or the input ground is short-circuited to the output negative pole.

Judgment method: Check whether the N line of the power module/input ground-output ground is short-circuited, and check whether there is a negative ground point on the back-end load board;

Solution: It is not recommended that customers connect the isolated power module N line/input ground-output ground together. If the actual application requires the negative pole to be grounded and the requirements for EMC and ripple noise are not high or there are no requirements for isolation voltage, the ground can be shared. use;

3) There are high-power and strong interference equipment or components near the power module

Solution:

a. The customer system layout keeps the power module away from high-power equipment;

b. Add filter peripheral circuit to the front end of the power module;

c. The output leads of the power module should be shortened to reduce noise coupling. If necessary, a metal shell can be used to shield external interference;