What is normal blood pressure for a 2-year-old? How can high blood pressure be detected in children? What are the causes of hypertension in kids? Get the answers to these pressing questions and more in this detailed guide on high blood pressure in children.

Understanding Normal Blood Pressure in Children

Contrary to popular belief, high blood pressure, or hypertension, is not just a condition that affects adults. According to the American Academy of Pediatrics (AAP), an estimated 3.5% of children and teens also experience this health concern. Monitoring and maintaining healthy blood pressure levels is crucial, as untreated high blood pressure can lead to serious complications, such as heart disease, kidney failure, stroke, and vision loss.

A child’s blood pressure is measured by the force of blood against the walls of their arteries. If this pressure is higher than normal, the heart has to work harder to pump blood throughout the body. Over time, this added strain can cause damage to various organ systems.

Checking Blood Pressure in Children

Children’s blood pressure should be checked annually starting at age 3, during their regular check-ups with the pediatrician. The child should sit comfortably in a chair with their feet supported and their arm level with their heart. The doctor or nurse will use a stethoscope and a hand-inflated arm cuff to measure the blood pressure.

If a child has a health condition that increases their risk of high blood pressure, such as obesity or kidney disease, their blood pressure will be checked at every doctor visit. If a child’s blood pressure is high during a regular check-up, it will be monitored more frequently.

Defining Normal and High Blood Pressure in Children

There is no single “normal” blood pressure that applies to all children. A child’s healthy blood pressure depends on their age, height, and gender. For children under 13, pediatricians use a percentile chart to compare their blood pressure to their peers of the same age, height, and gender.

A child is considered to have an elevated blood pressure if their reading falls above the 90th percentile, and hypertension if it’s above the 95th percentile. For teenagers over 13, the normal blood pressure ranges are the same as for adults: less than 120/80 mm Hg for normal, 120-129 mm Hg systolic (top number) and less than 80 mm Hg diastolic (bottom number) for elevated, and higher than 130/80 mm Hg for hypertension.

Identifying Symptoms of High Blood Pressure in Children

Hypertension is often a silent condition, meaning there are usually no obvious symptoms to alert parents that their child has high blood pressure. This is why regular blood pressure screenings are so important. Some children with high blood pressure may experience headaches, changes in vision, or dizziness, but these are not always present.

If your child complains of any of these symptoms, it’s crucial to contact their pediatrician immediately for further evaluation and diagnosis.

Causes of High Blood Pressure in Children

There are several potential causes of high blood pressure in children, including:

• Obesity or being overweight
• High-sodium diet (too much salt)
• Kidney disease
• Congenital or acquired heart disease
• Thyroid or adrenal disease
• Diabetes
• Genetic disorders (inherited from a parent or grandparent)
• Stress

When high blood pressure occurs in young children (under 6 years old), it is often due to an underlying medical condition, such as kidney disease. This is known as secondary hypertension. In older children and teens, primary hypertension, which is not linked to a specific disease, is more common and is often related to obesity.

Monitoring and Managing High Blood Pressure in Children

If a child’s pediatrician identifies a trend of high blood pressure readings, they will closely monitor the child’s blood pressure or refer the family to a specialist to address any health concerns. The child may be asked to wear a 24-hour, portable blood pressure monitoring device (called an ambulatory blood pressure monitor or ABPM) to provide a complete picture of their blood pressure throughout the day and night.

Depending on the underlying cause and severity of the high blood pressure, the child’s treatment plan may include lifestyle changes, such as a healthier diet and increased physical activity, or, in some cases, medication. Regular follow-up appointments and ongoing monitoring are essential to ensure the child’s blood pressure remains within a healthy range.

Prioritizing Children’s Health

While high blood pressure may not be the first health concern that comes to mind when thinking about children, it is a serious condition that requires vigilant monitoring and proactive management. By understanding the importance of regular blood pressure screenings, recognizing the signs of hypertension, and addressing the underlying causes, parents and healthcare providers can work together to ensure children maintain optimal cardiovascular health and avoid the potentially devastating consequences of untreated high blood pressure.

High Blood Pressure in Kids – Children’s Health

Share:

You may think that hypertension, or high blood pressure, is a condition that affects only adults. However, according to the American Academy of Pediatrics (AAP), an estimated 3.5% of children and teens have high blood pressure. When left untreated, this condition can cause serious complications, such as heart disease, kidney failure, stroke and vision loss.

“A blood pressure reading measures the force of blood against the walls of arteries. This pressure is what your heart has to pump against to get blood out to the rest of your body,” explains Alan Sing, M.D., a pediatric cardiologist at Pediatric Heart Specialists, a Children’s Health℠ Care Network Partner. “If blood pressure is higher, then the heart has to work harder. Over time, this high blood pressure can cause damage to different organ systems in the body.”

However, regular screenings can help identify high blood pressure in children. Learn more about what is considered high blood pressure for a child and ways you can help keep your child healthy.

How is a child’s blood pressure checked?

A child’s blood pressure should be checked once a year at their annual exam starting at the age of 3. Your child should sit comfortably in a chair with their feet supported and their arm level with their heart. Your child’s physician or nurse will use a stethoscope and a hand-inflated arm cuff to check their blood pressure.

If a child has a health condition that increases their risk for high blood pressure, such as obesity or kidney disease, their blood pressure will be checked at every doctor visit. If a child’s blood pressure is high at a well-child visit, their blood pressure will also be checked more frequently.

Your child’s pediatrician will track trends in blood pressure over time, not just the initial screening, to accurately identify a diagnosis of hypertension.

What is a normal blood pressure for a child?

There isn’t one single number or blood pressure that is considered normal for all children. A healthy blood pressure for a child depends on their age, height and gender.

For children under the age of 13, your pediatrician will use a percentile chart to compare your child’s blood pressure to peers of the same age, height and gender. This allows a more precise indication if a young child is showing high blood pressure. A child is considered to have an elevated blood pressure if their blood pressure falls above the 90th percentile, and hypertension if they are above the 95th percentile.

Over the age of 13, normal blood pressure ranges are the same for teenagers as they are for adults:

• Normal blood pressure: Less than 120/80 mm Hg
• Elevated blood pressure: Systolic (top number) between 120-129 mm Hg and diastolic (bottom number) less than 80 mm Hg
• Hypertension: Top or bottom number higher than 130/80 mm Hg

If your child’s pediatrician notices a trend of high blood pressure readings, they will closely monitor your child’s blood pressure or refer you to a specialist to address any health concerns. They may have your child wear a 24-hour, portable blood pressure monitoring device (called an ambulatory blood pressure monitor or ABPM). This can be worn at home during your child’s normal routine and takes measurements every 20 to 30 minutes during the daytime and 30 to 60 minutes at night.

This monitor can help your child’s pediatrician decide whether your child needs further tests or treatment by giving a complete picture of blood pressure throughout the day and night.

What are signs of high blood pressure in kids?

Hypertension is often a silent condition. Typically, there aren’t obvious symptoms to let parents know their child has high blood pressure; it is often diagnosed when the doctor discovers it during an exam. This is why regular blood pressure screening is so important.

Some children with high blood pressure may experience frequent headaches, changes in vision or dizziness. If your child complains of these symptoms, contact your pediatrician.

What are causes of high blood pressure in kids?

A child’s blood pressure might be high when it is measured for many reasons, such as stress, illness, recent physical activity, a true hypertension issue or a medical condition.

Causes of high blood pressure in kids can include:

• Obesity or being overweight
• High-sodium diet (too much salt)
• Kidney disease
• Congenital or acquired heart disease
• Thyroid or adrenal disease
• Diabetes
• Genetic disorders (inherited from a parent or grandparent)
• Stress

When a young child (under 6) has high blood pressure, the cause is often a related medical condition, such as kidney disease. This is called secondary hypertension.

When high blood pressure has no disease-related cause, it’s called primary hypertension. Primary hypertension is more common in older children and teens and is commonly related to obesity or to a family history of hypertension.

“There is a growing trend in the number of children and teens who are overweight or have obesity, and this is a major cause of high blood pressure in kids,” says Smitha Vidi, M.D., a pediatric nephrologist at Children’s Health and Assistant Professor at UT Southwestern. “Additionally, kids are eating a lot of processed foods, which have very high amounts of salt. A high-salt diet is a big contributor to increasing blood pressures.”

How is high blood pressure treated in children?

If your child is diagnosed with hypertension, your pediatrician may recommend certain lifestyle changes to lower their blood pressure, such as a healthy diet, regular exercise or weight loss.

• DASH diet: Designed from research sponsored by the National Institutes of Health, the DASH diet focuses on eating fruits, vegetables, low-fat dairy, nuts, beans and seeds.
• Exercise: The AAP recommends children and adolescents get 60 minutes or more of physical activity daily (includes outside play and team sports).
• Low-sodium diet: Sodium is the scientific name for the salt in food. In addition to watching table salt usage, be cautious of how much processed food your child eats.

If needed, your child’s physician may prescribe medications to control blood pressure. These medicines are the same ones adults take, just in age and weight-appropriate doses. Your child’s physician can choose the best medication for your child based on their individual health profile and risk factors.

You can help your child prevent high blood pressure and complications. Talk about the importance of a healthy lifestyle and continue to be a good role model – making healthy food choices and engaging in exercise as a family.

“Taking steps as a family to stay healthy is key to preventing hypertension in children,” says Dr. Vidi. “Try to devote a little of your time each day to doing fun activities with your kids, such as biking, dancing, swimming or even walking to a nearby park. “

Learn more

No matter the reason behind a child having high blood pressure, Children’s Health can provide expert, multidisciplinary care. Learn more about hypertension in kids and how we can help.

Thank you!

You are now subscribed to the Children’s Health Family Newsletter.

Children’s Health will not sell, share or rent your information to third parties.
Please read our privacy policy.

Children’s Health Family Newsletter

Get health tips and parenting advice from Children’s Health experts sent straight to your inbox twice a month.

Please enter a valid email address

American Academy of Pediatrics, determinants of health, diet, heart health, hypertension, obesity, overweight, primary care

Vital Signs in Children | Kaiser Permanente

Skip Navigation

Overview

Vital signs include heart rate, respiration (breathing rate), blood pressure, and temperature. Knowing the ranges for vital signs for your child can help you notice problems early or relieve concerns you may have about how your child is doing.

0 to 12 months old

Vital signs for infants ages 0 to 12 months include the following:

Heart rate

This is measured in beats per minute (bpm).

• 0 to 12 months: 70-190 bpm^{footnote 1}

Respiration (breaths)

This is measured in breaths per minute (bpm).

• 0 to 6 months: 25-64 bpm
• 6 to 12 months: 22-61 bpm^{footnote 2}

Temperature

This is measured in degrees Fahrenheit (F) or Celsius (C).

• 0 to 12 months: 98.6 °F (37 °C). The normal range is 97.4 F–99.6 F (36.3 C–37.6 C).

1 to 11 years old

Vital signs for children ages 1 to 11 years include the following:

Heart rate

This is measured in beats per minute (bpm).

• 1 to 11 years: 52-156 bpm^{footnote 2}

Respiration (breaths)

This is measured in breaths per minute (bpm).

• 1 to 3 years: 21–33 bpm
• 4 to 11 years: 17-25 bpm^{footnote 2}

Blood pressure (systolic/diastolic)

Systolic blood pressure is the upper number of a blood pressure reading. Diastolic is the lower number. They are measured in millimeters of mercury (mm Hg).

What is normal and what is high blood pressure depends on your child’s age, sex, and height.^{footnote 3}

Temperature

This is measured in degrees Fahrenheit (F) or Celsius (C).

• 1 to 11 years: 98.6 °F (37 °C). The normal range is 97.4 F–99.6 F (36.3 C–37.6 C).

12 years and older

Vital signs for children ages 12 years and older include the following:

Heart rate

This is measured in beats per minute (bpm).

• 60–110 bpm^{footnote 1}

Respiration (breaths)

This is measured in breaths per minute (bpm).

• 12–22 bpm^{footnote 2}

Blood pressure (systolic/diastolic)

Systolic blood pressure is the upper number of a blood pressure reading. Diastolic is the lower number. They are measured in millimeters of mercury (mm Hg).

For children who are age 12, what is normal and what is high blood pressure depends on your child’s age, sex, and height.^{footnote 3}

For children who are 13 and older, normal blood pressure is 120/80 mm Hg or lower.^{footnote 3}

Temperature

This is measured in degrees Fahrenheit (F) or Celsius (C).

98. 6 F (37 C). The normal range is 97.4 F–99.6 F (36.3 C–37.6 C).

References

Citations

1. Bernstein D (2016). Evaluation of the cardiovascular system: History and physical examination. In RM Kliegman et al., eds., Nelson Textbook of Pediatrics, 20th ed., vol. 2, pp. 3120–3127. Philadelphia: Elsevier. https://ebookcentral.proquest.com. Accessed January 6, 2022.
2. Fleming S, et al. (2011). Normal ranges of heart rate and respiratory rate in children from birth to 18 years: A systematic review of observational studies. Lancet, 377(9770): 1011–1018. DOI: 10.1016/S0140-6736(10)62226-X. Accessed January 6, 2022.
3. Flynn JT, et al. (2017). Clinical practice guideline for screening and management of high blood pressure in children and adolescents. Pediatrics, 140(3): e20171904. DOI: 10.1542/peds.2017-1904. Accessed August 31, 2018.

Credits

• Top of the page

• Next Section:

  Related Information

How to choose a power supply – a quick guide – Hardware on DTF

32 914
views

This article is a small guide and will tell you about choosing a power supply for your personal computer. At the end there will be a kind of tl;dr – those who wish can go directly to it.

Well, let’s get started!

You select PC components for your immediate needs. What components do you start with? I’ll try to guess: from the processor and video card. What’s next? RAM, motherboard and drives? Cooling system, case and monitor?

What about the power supply?

PSU is that PC element that people think about last, sometimes leaving its purchase “for change” and not attaching serious importance to its critical role in any assembly. But in vain. After all, the right choice of PSU can save you from many problems, starting with the unstable operation of the entire system and ending with a fatal component failure.

In this short “dummies’ guide” (without going deep into circuitry, serious analysis of power circuits and detailed consideration of standards), we will look at the main characteristics of power supplies and points that you should pay attention to when choosing a PSU.

PSU – the heart of your PC

The

PSU is the sole source of power for all of your PC’s components and is responsible for providing stable and correct power.

The main tasks of the BP are as follows:

1. “Rectification” of the current.

The mains uses alternating current. The components of your PC, in turn, need a constant. Converting AC to DC and provides power supply.

2. “Delivery” of current of various voltages to the elements of your PC

Different components of your computer require different supply voltages, and some components require several power lines with different voltages at once. The main voltage lines are +3.3V , +5V and +12V . The most powerful consumers (processor, video card and northbridge) use lines +12V and +5V .

Characteristics of power supplies.

Power

The main characteristic of a PSU is its power, measured in watts. The value of the power supply unit for the stable operation of our system must be no less than the value that our system consumes in maximum performance mode. The most “gluttonous” consumers include a video card and a processor. The remaining components consume less electricity.

For an approximate calculation of the PSU power suitable for our system, it is necessary to add up the energy consumption values ​​of all system components and add up to 20% “in reserve”, thereby laying a certain reserve.

It’s easy to find out the amount of power consumption of a processor and a video card: just look at the description of this parameter in their performance characteristics. When overclocked, these components begin to consume significantly more electricity than in stock mode – tests tell about this in detail.

An example of increasing the power consumption of the i7-9700K processor at various stages of overclocking

Also, when calculating the maximum possible consumption of a video card, you can focus on the number of connectors and their allowable power transfer limits: PCI-E 16x – 75 W, 6 -pin – 75 W, 6 + 2 -pin – 150 W. Thus, the theoretical power consumption limit of a video card with two 6-pin and 6+2-pin connectors is limited to 300 watts.

The power consumption of the motherboard depends on the following factors: the number of power phases, the type of voltage regulator, the chipset and additional modules (integrated sound chip, Wi-Fi module, the number of ports and connectors and their type). As a rule, motherboards consume around 40-50 watts, but the power consumption of some top models can reach 80 watts or more under heavy load.

The optical drives should also be considered in the calculation: their power consumption can be up to 30 W for some models of SATA DVD and Blu-Ray drives.

Data drives are generally not major energy consumers. When calculating the approximate power consumed by the system, the amount of electricity consumed can be taken as: 8-10 W for each hard drive, and 3 W for each SSD.

Elements of the cooling system (both processor and additional case fans) are often not considered as serious consumers of electricity – and in vain. 120mm and 140mm fans, when operating at 2000 rpm, can consume up to 6-7 watts each, depending on the model. Therefore, they definitely need to be considered, especially if there are several such turntables inside the case. Up to 20 watts can be put on the processor cooling system itself, whether it’s a tower cooler or an AIO dropsy.

The RAM is one of the most economical consumers in the system, so 5 watts per stick should be more than enough. The power consumption of RAM is weakly correlated with its volume, that is, an 8 GB bar will consume almost as much as a 4 GB bar, all other things being equal.

To facilitate the calculation of the total power consumption of , you can use specialized programs or online calculators on the websites of PSU manufacturers. From myself, I recommend this one as an easy-to-use and visual version of the power calculator.

efficiency

High power does not guarantee the quality of the PSU and its efficiency. The efficiency of the power supply is evidenced by its efficiency.

The efficiency of the power supply shows how much power from the network goes to your system. The higher the efficiency value, the less the power supply heats up, consuming electricity more efficiently. Due to less heating, both a better temperature regime and a quieter operation of the cooling system are ensured.

Power supply efficiency rated to 80 PLUS. This standard implies several levels of performance, in ascending order:

• 80 PLUS White/Standard
• 80 PLUS Bronze
• 80 PLUS Silver
• 80PLUS Gold
• 80PLUS Platinum
• 80 Plus Titanium

As you can see from the table, the main difference between the various levels of certification of the 80 PLUS standard is the efficiency of the power supply at loads of 20%, 50% and 100%. The higher the level to which the PSU corresponds, the higher its efficiency and, accordingly, the price.

Poorly designed power supplies are generally not certified, so 80 PLUS compliance is an added guarantee of quality. You can check the actual compliance of the PSU with the 80 PLUS standard on the Plug Load Solutions website.

Current on individual lines

The total power of the power supply is the sum of the powers it can provide on the individual power lines. If the load limit on one of the lines is exceeded, the system may lose stability, even if the total power consumption is far from the nominal. As mentioned above, the main lines of force are +3.3V , +5V and +12V :

• +12 volts are supplied primarily to the video card and processor. On this line, the power supply must provide as much power as possible
• +5 volts supplied to the motherboard, drives and optical drives
• +3. 3 volts are supplied to the motherboard and RAM.

Information on the power lines and the current transmitted through them is available on the technical data sheet of the PSU as a sticker (the application of information and its appearance may differ depending on the PSU model / manufacturer). Most often it is expressed as a description of the maximum load.

An example of a sticker with performance characteristics – designations of current and power on power lines

Power factor correction

The power factor correction module (Power Factor Correction, PFC) allows you to increase the efficiency of the power supply. It is a special element designed for power factor correction and aimed at protecting the network.

PFC modules are divided into active and passive. An active power factor correction (APFC) module equalizes the input voltage, allowing stable operation of all devices that output an analog signal from the computer. PSU models with APFC are more expensive than models with a passive version of this module.

Dimensions and form factor. Weight.

Let’s consider the most common modern standard for the PSU of the mass segment – ATX.

The ATX standard guarantees dimensional compatibility with standard ATX cases and electrical specifications for ATX motherboards.

In most cases, the only electrical specification that matters to us will be ATX12V 2.x.

A standard ATX format power supply has dimensions of 150mm * 86mm in width and height, while the length (aka depth) varies depending on the model.

If you decide to build a compact system and the space for the power supply is limited by the small size of the case, you should take a closer look at the SFX and SFX-L form factor devices.

Comparison of ATX, SFX-L and SFX PSU dimensions (from largest to smallest) Source: smallformfactor.net

They feature more compact dimensions while still meeting the ATX12V 2. X standard in terms of electrical performance.

The weight of a power supply usually indicates the quality of the components used. The heavier the power supply, the better. Weight is not an absolute indicator when choosing, however, a suspiciously light PSU should immediately lead you to the idea that the product is not of the highest quality.

Cable management

With regard to the method of fixing cables, power supplies can be divided into three main groups:

• Non-modular PSU
• BP partially modular design (semi-modular)
• PSU fully modular (full modular)

The main difference between the types of construction is the ability to disconnect the complete wires and install only the ones you need in the quantity that your system components need. Let’s look at them in a little more detail:

1. Non-modular

The main feature is that all supplied cables for all connectors are connected to the PSU without the possibility of disconnecting them.

As such, this design has no advantages, but “macaroni” can be written as a minus – it can be difficult to achieve a neat management of all cables. If you don’t need some complete cables due to the small number of components in your system, then remove them you can’t – they will remain inside the case of the system unit.

2. Semi-modular

Only the main cables go without detachment: 24-pin ATX, PCIE, 8-pin cable for the CPU and one or two SATA/MOLEX cables for peripherals.

The main plus is easier cable management and efficient organization of space inside the system unit.

3. Full Modular

Full modular design allows you to disconnect any cables from the PSU, thus adjusting everything for yourself.

Of the benefits – the easiest of all three types of cable management and the most efficient organization of space inside the system unit.

An important consideration when considering cable management options is their sheathing. It allows you to avoid clamps and fractures when organizing space inside the system unit, and also greatly simplifies installation.

Cooling.

Depending on its characteristics, size and form factor, the power supply can be equipped with a fan size from 40mm to 140mm.

Many modern models allow you to adjust the fan speed, thereby achieving a reduction in noise level. But do not forget about the cooling efficiency of a PSU with not the highest efficiency.

Upgrading stock cooling to higher quality is a common option among enthusiasts. Installing a better fan can, in some cases, significantly improve temperature performance.

Some models are equipped with a so-called “hybrid cooling system”. This term is used to automatically turn off the fan when the load on the PSU is low (for example, when the system is idle). This allows, to a certain extent, to reduce the noise emission of your assembly, but is not a mandatory element of the power supply.

Manufacturer’s warranty.

Typical power supply warranty options are 2 years, 3 years, 5 years, 7 years, and 10 years. It would be logical to assume that the longer – the better for the consumer. A long warranty period also indirectly indicates the quality of the PSU – the manufacturer is confident in a lower probability of component failure over time.

Manufacturer

Again, everything is quite simple – a well-known brand and the presence of good reviews on the trading floors allow you to make the right choice. Personally, I would recommend a PSU from Corsair, EVGA, Seasonic, Chieftec, Silverstone. But that doesn’t mean that Thermaltake, Enermax, Cooler Master, NZXT, and others make bad PSUs.

It is also worth noting that behind all the variety of manufacturers of power supplies and their lines on the market, there are basically the same OEMs. Most well-known companies do not have their own production, and you can find out the real manufacturer by markings on the boards inside the power supply.

Certification

FCC, CE, UL, TUL approval and certification is an important consideration when choosing a device. And if FCC and CE certification is de facto mandatory for most consumer devices, then passing additional third-party certifications is at the discretion of the manufacturer, and is a sign of the quality of the device.

In addition to being mandatory, most PSUs are also certified by Underwriters Laboratories and TÜV.

The American company Underwriters Laboratories is engaged in standardization and certification.

UL listed power supplies are specially marked with their logo and serial number. By this serial number, starting with the letter E, you can determine the manufacturer and view the PSU parameters. To do this, simply enter this serial number in the online UL database.

As a result, you will receive information about the real PSU manufacturer, as well as a link to a document that contains the main characteristics of the device, including the maximum load on the lines.

Example of designation of different types of certification

TÜV is a German organization responsible for product safety control. It includes three holdings: TÜV SÜD, TÜV Rheinland and TÜV Nord.

Similar to UL certification, TÜV-certified power supplies have the company logo and certificate serial number imprinted on their body. Also, similar to UL certification, this serial number can be entered on the TÜV website and get detailed information about the device.

Please note that the full information on UL and TÜV certification may not be applied to the label on the power supply itself, but located on the box. In extreme cases, you can contact the manufacturer’s support service to clarify the availability of a specific type of certification.

TL;DR

To summarize. How to choose a power supply?

So, the following points must be considered:

• Sufficient power. Choosing a PSU with 15-20% headroom will avoid system stability issues and provide headroom for overclocking components and possible upgrades in the future
• High efficiency. Consider buying an 80 Plus certified PSU, the more efficient the better
• Sufficient power on +12V lines for main consumers (video card and processor)
• Presence of PFC module
• ATX12V 2.X Compliant
• Cable connection diagram. A fully modular design is the preferred allows you to assemble the system with greater ease and more efficiently organize the space inside the system unit
• A trusted and reputable manufacturer that provides a long-term power supply warranty (minimum 5 years, preferably all 10)
• Certification FCC, CE, UL, TÜV
• Power supply weight. The more the better
• Quality cooling in accordance with the declared characteristics.

Thank you for your attention. All the best and high-quality pieces of iron.

Post written by a member of the Independent Authors Community DTF

Got ideas for cool articles? Join now! , Our discord server and telegram chat

Power supplies. Safety requirements, connection and installation features

• Safety requirements, connection and installation features

Lighting in the apartment

04/27/2022

Power supply selection and safety requirements

So, let’s start with the selection of the power supply. The algorithm for selecting a power supply is shown below.

Figure 1 – PSU selection algorithm.

Now in order:

• Which series of power supply to use depends on the installation conditions. Wide or narrow space, whether moisture protection is needed, all this determines the type of case, and hence the series. Do not use unprotected blocks in the bathroom or outdoors. The moisture condensate formed on the radio components will quickly disable the unit.
• The voltage must strictly correspond to the rated voltage for the load (for example, tape). However, if the power is very high, or the connecting wire is too long, it is worth considering the selection of the entire system for 24 volts, including both the power supply and the tape.
• The power of the power supply must be greater than the total power of all consumers connected to it. And the more stock, the better. For example, for installation in a well ventilated cool and free space, a margin of 20% can be made. And in the case of installation in a narrow closed niche or in a hot place without ventilation, the stock should be increased to 40%.
• Figure 2 – Graph of load versus temperature.
• Powerful open power supplies in their design have a cooling fan that emits a hum when the unit is running. This is not critical when installing in a shop or exhibition pavilion, but is very important in residential areas. In this case, it is worth offering the client a sealed unit of the same capacity, or dividing the load into several less powerful units without a fan.
• Figure 3 – Cooling fan.
• Do not install power supplies near heat sources, as this may cause them to overheat.
• When installing several power supplies, you need to remember that for their normal cooling, there must be a free space of at least 5 cm on each side between the cases of adjacent units.
• Figure 4 – Scheme of installation of several PSUs.
• It is advisable to mount the blocks on a metal surface. In this way, the cooling of the unit can be improved.
• Never connect the output wires or terminals of the unit to a 220V network. The block will permanently fail. If you are not sure about the correct connection, it is better to check everything again in accordance with the instructions on the block body.
• Figure 5 – Scheme of incorrect connection of the PSU.
• The outputs of switching power supplies cannot be interconnected, you need to divide the load into parts, and power each part from its own power supply (when controlled through a controller, each part is connected to its own unit through an amplifier).

Power Supply FAQ

Well, a little about the issues that may arise during the operation of power supplies:

• Heating of the block body up to 70 degrees is considered normal operating mode, as the body dissipates heat from the power elements of the block. If the case temperature exceeds 70 degrees, you need to reduce the load, or replace the unit with a more powerful one.
• If an LED strip is connected to the unit via a PWM dimmer or controller, and during operation at medium brightness levels, you hear a squeak emitted by the unit, this is not a malfunction. All switching power supplies emit a squeak or crackle when dimmed through PWM dimmers, louder or quieter, but in any case, there is sound. This is a feature not so much of the power supply as of the principle of operation of PWM dimmers, which connect and disconnect the load at a high frequency (200-750Hz). The windings of a small pulse transformer vibrate at the moment the load is turned on and off, making a squeak (Similar to power grid transformers buzzing at an industrial frequency). There is a way to make the squeak much quieter. Installing additional capacitors at the output of the unit may make the squeak quieter, but it can cause other problems, such as an explosion of this very capacitor if it is of poor quality or incorrectly selected, so it is strongly not recommended to try to solve the problem with such “crutches”. At the moment, there are no guaranteed and safe ways to remove the squeak of existing power supplies, it is better to find out from the client in advance the purpose of purchasing the unit. If you plan to use it in a residential area, and with dimming, then you should immediately recommend the quietest units from our range, the LV and XTW series. If the client has already bought the block, and now complains about the squeak, then change the block to LV or XTW. Developments in this area are ongoing, and we may soon also have a line of non-hermetic units that are silent when dimming.
• If, after turning off the power, the tape connected to the unit continues to flash occasionally for a short time, this is also not a malfunction of the power unit. This most often happens if the power supply is connected via a backlit switch. The principle of operation of such a backlight is simple, in the off position, a light bulb or backlight LED conducts a small current through itself, bypassing the switch, that is, this current flows through the consumer, which is controlled by the switch. The backlight in the switches was invented back in the era of classic incandescent lamps, and did not affect their operation in any way, since the leakage current is too small. However, there are capacitors in switching converters such as power supplies or LED light drivers. The small leakage current created by the backlight in the switch gradually charges the capacitors up to the operating voltage. When the capacitors are charged, the power supply controller turns on and drains the stored energy into the tape, causing a flash. Then, this process is repeated over and over again. In order to prevent the accumulation of energy in the capacitors, it is necessary to connect a resistor with a resistance of 1 MΩ between its input terminals (L and N). The resistor will conduct leakage current through itself, bypassing the power supply.
• Figure 6 – Illumination of the switch.

Self-test questions:

1. Can the power supply be installed in a tight, non-ventilated niche? If yes, what needs to be considered?
2. It is necessary to power the tape with a power of 300W through a dimmer. Can it be powered by two 200W units? If yes, what is the right way to do it?
3. Unit beeps when dimming. What to do?
4. The light is off, but the tape flashes occasionally. What to do?
5. The unit heats up to 65 degrees during operation. What to do?

Read more on the topic

05.05.2023

Work of salons in shopping malls “Kashirsky Dvor” and “Maxlevel”

News

03.13.2023

Professional lighting design training from SWG

News

10.26.2022

Our company participates in Art Dom 2022

News

03/06/2022

LED modules. Device. Types of modules. Installation and connection

Lighting in the apartment

03/06/2022

TOP 6 ideas for using SWG LED strip in the interior

Lighting in the apartment

03/06/2022

220V tape, connection and installation features

Lighting in the apartment

03/06/2022

Lighting for a large office in the center of Moscow: selection and features

Lighting in the apartment

03/06/2022

NON-BORING COUNTRY HOUSE LIGHTING

Apartment lighting

03/06/2022

FITNESS CENTER LIGHTING

Apartment lighting

02/06/2022

Why is there no bin on the RGB tape?

Lighting in the apartment

04.