#power supply 10 ampere

[diyelectricaltech]

Nice-power DC Power Supply Variable 30v 10a - Laboratory 60V 5A

[zvaigzdelasas]

China’s state-owned power generation enterprise Datang Group said on June 30 that it had connected to the grid a 50 MW/100 MWh project in Qianjiang, Hubei Province, making it the world’s largest operating sodium-ion battery energy storage system. The project represents the first phase of the Datang Hubei Sodium Ion New Energy Storage Power Station, which consists of 42 battery energy storage containers and 21 sets of boost converters. It uses 185 ampere-hour large-capacity sodium-ion batteries supplied by China’s HiNa Battery Technology and is equipped with a 110 kV transformer station. Previously, the largest operational sodium-ion system was China Southern Power Grid’s Fulin 10 MWh BESS project, located in Nanning, southwestern China. The power station, which represents the first phase of a 100 MWh project, also features HiNa Battery’s cells.

2 Jul 24

The 100,000 kWh project in the Hubei province is capable of storing enough electricity to power 12,000 homes on a single charge.[...]

Sodium-ion batteries offer a number of benefits compared to conventional lithium-ion batteries, as they are both cheaper and safer than the batteries found in smartphones and electric cars.[...]

The sodium (Na) required to build them is also 500 times more abundant than lithium. while also holding the potential for greater charge and efficiency than Li-ion batteries.[...]

“Sodium-ion batteries have excellent safety and low-temperature operating performance,” said Cui Yongle, a project manager at Datang Hubei Sodium Ion Energy Storage.

“They can still guarantee 85 per cent charge and discharge efficiency at minus 20 degrees Celsius, which is unmatched by other batteries. They can also guarantee 1,500 charge and discharge cycles at a high temperature of 60 degrees Celsius. Their puncture resistance and impact resistance are much better than that of ordinary batteries.”

3 Jul 24

[sycompower]

What is UPS?

What is UPS?

In this block we see following points

What is UPS?

UPS block diagram

How UPS works?

UPS power range and backup time

Now we will discuss

What is UPS and its functionality?

UPS stands for Uninterruptable Power Supply. It is an electronic power supply which leads for enable some load for short period of time when electricity goes off.

There are Two Types of UPS system

Offline UPS

Online UPS

How UPS Works?

Simply UPS means provides uninterrupted power to the AC load. This AC load converts into DC power. It is also known as standby or emergency power supply and standby generator. After light shut down it switch into the battery bank power and provides 10-15 minutes standard backup time at full load.

In operating conditions, the current is drawn from the main AC power supply or power grid, while Online UPS provides load current in case of a power failure. Here the battery is used as the backup source to transfer power to the load in case of power break.

UPS power range and backup time

Each UPS have different output power, which is designed and calculated according to the connected load. Usually, the output power is shown in the volt-ampere (VA) unit. The common online or offline UPS output power in the market are 600VA, 1kVA, 1.5kVA, 2kVA, 6kVA, 10kVA, 15kVA, and 20kVA and also available in higher kva e.g30Ka, 100Kva etc. Backup time is the time that UPS can provide the connected load/loads and depends on how many batteries UPS has.

Advantages of UPS

Here are some advantages of Uninterruptable Power Supply

Highly reliable

Better protection

Noise free

Offers continuous power

In case of main power failure, no need to change the operation mode.

Negligible transfer time.

Wide Input voltage range

Disadvantages of UPS

Every machine has own drawbacks.

It generates more heat because of continuous power on

Complex design

High Power Loss

We Sycom Power Protection Pvt. Ltd provides all range of online and line interactive UPS. We provide Pan India service of batteries, UPS, Inverters and stabilizer. For more details please contact us www.sycompower.com

[onlineupsprice15]

In today’s fast-paced world, power interruptions can be more than just an inconvenience—they can disrupt our entire daily routine. That's why investing in a reliable power backup system is crucial. One of the key components of an effective backup system is the inverter battery. If you're on the hunt for the best inverter battery for your home, you've come to the right place. At Online UPS Price, we specialize in providing expert advice and affordable solutions for all your power needs. Let’s explore everything you need to know before choosing the ideal inverter battery for your home.

Why Do You Need an Inverter Battery?

Inverter batteries are the powerhouse behind any inverter system. They store electricity, which is converted from AC to DC and back again to provide backup power when needed. Whether it's for powering essential appliances like fans and lights or more energy-intensive devices like refrigerators and air conditioners, a high-quality inverter battery ensures that your home stays powered during blackouts. “best inverter battery for home”

Factors to Consider When Choosing the Best Inverter Battery

When searching for the best inverter battery for your home, it’s important to consider several key factors. Here's a breakdown of the most important ones:

1. Battery Capacity (Ah - Ampere Hours)

The capacity of an inverter battery is one of the most crucial factors. It determines how long your battery can power your home during a power outage. The higher the capacity (measured in ampere-hours, or Ah), the more power your battery can store and supply. For most households, a battery between 100 Ah and 220 Ah is typically sufficient, but the right size depends on the number of devices you want to run.

2. Battery Type

There are several types of inverter batteries available, and each has its pros and cons:

Lead-Acid Batteries: These are the most common type of inverter batteries, known for being affordable and easily available. However, they require regular maintenance, such as water top-ups, and have a shorter lifespan.

Tubular Batteries: Tubular batteries are more durable and have a longer lifespan than lead-acid batteries. They are ideal for homes that experience frequent or prolonged power cuts. While they are more expensive, the reduced maintenance and longer life often make them a better long-term investment.

Lithium-Ion Batteries: These are the most advanced and efficient inverter batteries on the market. Lithium-ion batteries are compact, require no maintenance, and have a longer life span. However, they come with a higher price tag, making them ideal for those looking for a premium, hassle-free option.

3. Backup Time

Backup time is another essential consideration. This refers to how long the inverter battery can keep your appliances running during an outage. It varies depending on the battery's capacity and the power consumption of the devices connected to it. For instance, a 150 Ah battery could provide power for around 3-4 hours for a few basic appliances. It’s essential to estimate your power needs based on the number of devices and appliances you want to run simultaneously.

4. Inverter Compatibility

Ensure that the inverter battery you choose is compatible with your existing inverter. Most batteries will work with various inverter brands, but it’s important to check the specifications to ensure optimal performance. “best inverter battery for home”

5. Warranty and Lifespan

Inverter batteries come with varying warranty periods, typically ranging from 2 to 5 years. It’s a good idea to opt for a battery with a longer warranty as it indicates the manufacturer's confidence in the product. Additionally, you should consider the expected lifespan of the battery, as some models may last up to 8-10 years with proper care.

6. Price

While price is always a factor, it’s crucial to balance cost with quality. Investing in a high-quality battery may have a higher upfront cost, but it will save you money in the long run through extended lifespan, better performance, and lower maintenance needs. At Online UPS Price, we provide competitive pricing for all types of inverter batteries, ensuring you get the best value for your investment.

Top Brands to Consider

At Online UPS Price, we offer a wide selection of trusted brands known for producing high-performance inverter batteries, including:

Luminous

Exide

Amaron

Microtek

Okaya

These brands are recognized for their reliability, long-lasting performance, and robust warranty policies.

Final Thoughts: Choosing the Best Inverter Battery for Your Home

Selecting the best inverter battery for your home doesn't have to be overwhelming. By considering factors like battery capacity, type, backup time, and price, you can make an informed decision that will keep your home powered during outages. At Online UPS Price, we are committed to helping you find the best power solutions at affordable prices. “best inverter battery for home”

Feel free to explore our extensive catalog of inverter batteries, and don’t hesitate to reach out to our team of experts for personalized recommendations.

[digitalsanshta]

In today's fast-paced digital world, businesses and individuals alike depend heavily on continuous, reliable power to keep their operations running smoothly. Whether it's for data centers, industrial applications, or sensitive electronics, having an uninterruptible power supply (UPS) is essential. The Vertiv 10 kVA Online UPS, available at Online UPS Price, is a top-tier solution designed to provide uninterrupted power and protect your equipment from the risks of power failures.

What is a 10 kVA Online UPS?

A 10 kVA Online UPS (Uninterruptible Power Supply) is a powerful device designed to provide a consistent and clean power supply to critical equipment. The term "kVA" stands for kilovolt-amperes, a unit of power that measures the capacity of the UPS. In simpler terms, a 10 kVA UPS is capable of supporting equipment with a total power requirement of up to 10,000 VA (volt-amperes).

The "Online" in the name refers to the UPS's operating mode. Unlike other types of UPS systems, an online UPS continuously filters and conditions the incoming power from the grid, ensuring that the connected equipment always receives a clean and stable power supply. This makes it ideal for environments where even the slightest power interruption could cause significant damage or data loss.

Key Features of the Vertiv 10 kVA Online UPS

The Vertiv 10 kVA Online UPS is packed with features that make it a standout choice for businesses and individuals seeking a reliable power backup solution. Here are some of the key features that set it apart:

1. Double Conversion Technology

The Vertiv 10 kVA Online UPS uses double conversion technology, which means that it converts incoming AC (alternating current) power to DC (direct current) and then back to AC. This process ensures that the power supplied to your equipment is completely free from any disturbances such as spikes, surges, or sags that can occur in the utility power.

2. High Efficiency

Efficiency is a critical factor when choosing a UPS, as it directly impacts operational costs. The Vertiv 10 kVA Online UPS boasts a high-efficiency rating, which means that it minimizes energy wastage, reduces heat generation, and lowers electricity bills. This makes it an eco-friendly choice as well as a cost-effective one.

3. Scalability

One of the significant advantages of the Vertiv 10 kVA Online UPS is its scalability. Whether you need to protect a small server room or a larger data center, this UPS can be easily scaled to meet your growing power needs. With its modular design, you can add more units as required, ensuring that your power protection evolves with your business.

4. Advanced Battery Management

Battery health is a crucial aspect of any UPS system. The Vertiv 10 kVA Online UPS comes equipped with advanced battery management features that prolong battery life and ensure optimal performance. The system monitors battery status in real-time, providing alerts for any issues, and offers automatic battery testing to prevent unexpected failures.

5. Intelligent Monitoring and Control

The Vertiv 10 kVA Online UPS includes intelligent monitoring and control capabilities, allowing users to manage and monitor their power supply remotely. With features like remote monitoring, event logging, and status notifications, you can stay informed about your UPS's performance and take proactive measures to address any potential issues.

Applications of the Vertiv 10 kVA Online UPS

The versatility of the Vertiv 10 kVA Online UPS makes it suitable for a wide range of applications. Here are some of the key areas where this UPS can be deployed:

1. Data Centers

Data centers require a constant and clean power supply to prevent data loss, downtime, and damage to sensitive equipment. The Vertiv 10 kVA Online UPS provides the reliable power backup needed to keep servers and networking equipment running smoothly.

2. Industrial Equipment

In industrial settings, power disruptions can lead to costly downtime and damage to machinery. The Vertiv 10 kVA Online UPS ensures that critical industrial equipment remains operational during power outages, protecting your investment and maintaining productivity.

3. Healthcare Facilities

Healthcare facilities rely on continuous power to operate life-saving medical equipment. The Vertiv 10 kVA Online UPS provides the peace of mind that comes with knowing that your critical healthcare devices are protected from power interruptions.

Why Choose Online UPS Price for Your Vertiv 10 kVA Online UPS?

Online UPS Price is a trusted supplier of high-quality UPS systems, offering competitive pricing and exceptional customer service. When you purchase the Vertiv 10 kVA Online UPS from Online UPS Price, you can expect:

Expert Guidance: Our team of experts is available to help you select the right UPS solution for your specific needs.

Competitive Pricing: We offer the best prices on Vertiv UPS systems, ensuring that you get the most value for your investment.

Reliable Support: Our after-sales support team is always ready to assist with installation, maintenance, and any technical issues that may arise.

Conclusion

The Vertiv 10 kVA Online UPS is a robust and reliable solution for ensuring uninterrupted power to your critical equipment. With its advanced features, high efficiency, and versatile applications, it is an excellent investment for businesses and individuals alike. When you choose Online UPS Price as your supplier, you can be confident that you are getting the best product at the best price, backed by unparalleled customer support. Don't leave your power needs to chance—invest in the Vertiv 10 kVA Online UPS today.

[romegamartxyc]

Top Industrial Spares Every B2B Buyer Needs for Efficient RO Purifier Operations

In the RO industry, top industrial spares include high-performance membranes like the Blue Max 300 GPD 4040, known for its efficient filtration and durability. Reliable pumps, such as the 300 GPD Motor Pump, enhance system performance with robust water flow. SMPS adaptors, including the Domestic 2 Ampere 24 Voltage variant, provide stable power supply for consistent operation. Control panels like the INFINITY A series offer advanced, microprocessor-based operational logic for precise management. Additionally, industrial pre-filter housings, like the Nextech 10-inch, are essential for protecting RO membranes by removing larger particles, ensuring long-term system reliability and efficiency.

[teardownit]

Review, teardown, and testing of RSP-150-24 Mean Well power supply

General description

A short description

The RSP-150-24 is a universal input power supply with a constant output voltage of 24 volts and a current of up to 6.3 amperes. According to the specification, it has an operating AC input voltage range of 85 to 370 volts without manual switching. The supply measures close to 7.8 × 3.9 × 1.2 inches (199 × 99 × 30 millimeters) and is made on a printed circuit board fixed to the base of the metal case, designed to operate with passive cooling. The top lid covering the case is perforated.

The power supply has an LED indication for the output voltage and allows one to adjust it within -5 to +10%. This unit does not have either PFC or thermal protection.

Design description

The input and output circuits of the power supply are connected to a common screw block (1). From left to right, there are three terminals for the input line, neutral, and ground wires, and two parallel blocks of two terminals for the outputs: ground and +24V.

The input voltage from the screw terminals is supplied to the RF interference filter (2) and through the fuse (3) to the diode bridge (5). Next, the rectified voltage is supplied to the active PFC, controlled by the PFC+PWM controller FAN4800 (4). The power part of the PFC is assembled using a MOSFET 19NM50N (6) and an 8A 600V ultrafast diode STTH8S06D (7). The output voltage from the PFC is supplied to the two-transistor forward converter, whose transistors, 14NM50N (9), are controlled by the same controller, FAN4800. The converter voltage from the transformer (10) is supplied to the rectifier and to the LC filter (13, 14). The output rectifier is made using MBR20150 diodes (12). The filter output capacitance is 470 uF, 35 V, designed for operating temperatures up to 220F (105C) (14).

General stabilization control is performed by the AP4310 chip. The control signal is transmitted from it to the high-voltage part of the circuit through a transistor optocoupler (15). One optocoupler serves as the main regulation channel, the second forms a backup channel for overvoltage protection (OVP), and the third provides reception of a remote control signal.

To limit the inrush current, there is an NTC (18) connected to the output stage of the rectifier bridge (5) near the boost inductor PFC.

The rectifier bridge (5), transistors, and diodes (6, 7, 9, and 12) are pushed against the housing with screws using overhead metal strips. Between the aluminum case and the board (from the solder side), there is an extra insulation layer, a thin sheet of fiberglass. All bulky components are additionally fixed using compound.

Build quality is good.

Test conditions

Most tests are performed using Metering Setup #1 (see appendices) at 80F (27C), 70% humidity, and 29.8 inHg pressure.

The measurements were performed without preheating the power supply with a short-term load, unless mentioned otherwise.

The following values were used to determine the load level:

Output voltage under a constant load

The high stability of the output voltage should be noted.

Power-on parameters

Powering on at 100% load

Before testing, the power supply is turned off for at least 5 minutes with a 100% load connected.

The oscillogram of switching to a 100% load is shown below (channel 1 is the output voltage, and channel 2 is the current consumption from the grid):

The picture shows three distinguishable phases of the power-on process:

1. The pulse of the input current charging the input capacitors when connected to the grid has an amplitude of about 4.5 A and a duration of about 5 ms.

2. Waiting for the power supply control circuit to start for about 50 ms.

3. (Output Voltage Rise Time) Output voltage rise takes 6 ms.

(Turn On Delay Time) The entire process of entering the operating mode from the moment of powering on is 61 ms.

(Output Voltage Overshoot) The switching process is aperiodic; there is no overshoot.

Powering on at 0% load

The power supply is turned off for at least 5 minutes before the test, with a 100% load connected. Then the load is disconnected and the power supply is switched on.

The oscillogram of switching to a 0% load is shown below:

The picture shows three distinguishable phases of the power-on process:

1. Charging the input capacitors when connected to the grid has an amplitude of about 1.5 A.

2. Waiting for the power supply control circuit to start for about 27 ms.

3. (Output Voltage Rise Time) Starting the converter, increasing the output voltage, and entering the operating mode take 4 ms.

(Turn On Delay Time) The entire process of entering the operating mode from the moment of powering on is 31 ms.

(Output Voltage Overshoot) The switching process is aperiodic; there is no overshoot.

Power-off parameters

The power supply was turned off at 100% load, and the input voltage at the moment of powering off was nominal. The oscillogram of the shutdown process is shown below:

The oscillogram shows two phases of the shutdown process:

1. (Shutdown Hold-Up Time) The power supply continues to operate due to the input capacitors holding charge until the voltage across them drops to a certain critical level, at which maintaining the output voltage at the nominal level becomes impossible. The phase takes 20 ms.

2. (Output Voltage Fall Time) Reduction of the output voltage, stopping voltage conversion, and accelerating the voltage drop take 6 ms.

(Output Voltage Undershoot) The shutdown process is aperiodic; there is no undershoot.

The current waveform at 100% load right before shutdown is close to sinusoidal with an amplitude of 2 A.

Output voltage ripple

100% load

At 100% load, the low-frequency ripple is approximately 15 mV.

At 100% load, the ripple at the converter frequency is approximately 50 mVp-p, and the noise is 70 mVp-p.

75% load

At 75% load, the low-frequency ripple is approximately 10 mV.

At 75% load, the ripple at the converter frequency is approximately 20 mVp-p, and the noise is 30 mVp-p.

50% load

At a 50% load, the low-frequency ripple is approximately 6 mV.

At 50% load, the ripple at the converter frequency is approximately 30 mVp-p, and the noise is 50 mVp-p.

10% load

At a 10% load, the low-frequency ripple is approximately 10 mV.

At a 10% load, the ripple at the converter frequency is approximately 30 mVp-p, and the noise is 50 mVp-p.

0% load

No-load current consumption measured with a multimeter: 29 mA.

(Power Consumption) The first assumption of excessive standby power draw of more than 6.5 watts is wrong, since the current in this mode is predominantly reactive. Indeed, the input filter in the circuit contains two capacitors with a combined capacitance of 1.5 μF.

Measuring the exact active power consumption at a 0% load with a basic set of instruments (oscilloscope, multimeter, etc.) is not possible.

At 0% load, the low-frequency ripple is approximately 2 mV.

At 0% load, ripples at the converter frequency are masked by the 80 mVp-p noise.

Dynamic characteristics

To evaluate the dynamic characteristics, a mode with periodic switching between 50% and 100% load was used. The oscillogram of the process is shown below:

It is clear that the power supply, when the load changes abruptly, allows for a slight dampening overshoot; the magnitude of the response to load changes is about 260 mV.

Overload protection

The claimed protection type is "constant current limiting, recovers automatically after the fault condition is removed." This was confirmed during testing. When the output is overloaded or shorted, the unit goes into current stabilization mode and automatically restores operation when the overload goes away.

The output current for the overload protection to kick in is 7.9 A.

Input circuit safety assessment

(Input discharge) Safety assessment is based on the discharge time constant of the input circuits when disconnected from the grid; the value is 0.126 s. This means that when operating on a 120 V input voltage, the time required to discharge the input circuits to safe values (<42 V) will be 0.2 s:

Important: The result is valid for this particular power supply unit; it was obtained for testing purposes and should not be taken as a safety guarantee.

The leakage current at the ground pin is 24 µA.

Thermal conditions

When operating with no load connected, no component overheating had been noticed.

Thermograms were captured at three power levels: 80, 90, and 100%, fully assembled and with the lid removed. Thermal images show that the most loaded element of the block is the input thermistor (NTC), and its heating seriously stands out against the background of all the other components. At 80% load, it heats up to 220F (104CC, 140F above ambient temperature). At 90%, it's 221F (105C, 141F above ambient), and at 100%, it reaches 236F (108C, 156F above ambient).

80% load

90% load

100% load

Conclusions

RSP-150-24 generally has little noise and ripple, the output voltage is maintained accurately, and the build quality is solid.

The dynamic characteristics of this unit aren't great; when the load pulses, the power supply can't adjust itself in time. This results in quite noticeable spikes and overshoots.

For long-term operation, the load should be limited to 70–80% of the nominal one., especially during the hot season when ambient temperatures reach 95F (35C) or more.

Important: The results are valid for this particular power supply unit; they were obtained for testing purposes and should not be used to evaluate all the units of the same type.

[hvacparts02]

Siemens Building Technology Gca126.1U-Sr 24Vac On/Off Aux Sw | PartsHnC

The Siemens Building Technology GCA126.1U, commonly known as the SR 24VAC On/Off Auxiliary Switch, is a simple yet essential component in a variety of HVAC systems. It runs on a 24-volt AC power supply and performs the duties of a manual control switch. You may quickly turn on or off linked devices, such as pumps, fans, and lights, with a flick. With a 10 Ampere, 250VAC, this switch can handle typical electrical loads. Simple installation involves wiring to defined terminals and usually mounting in an accessible area. The GCA126.1U has a green LED indication that visually confirms the on state. This switch improves user control and system adaptability, which is especially helpful in instances involving maintenance or troubleshooting. Its interoperability with 24VAC systems, although not specific to any one piece of HVAC equipment, makes it a useful tool for both building managers and technicians.

[fencefacts1]

Understanding Joules in Electric Fences

As a beginner, you might wonder what a joule is in the context of an electric fence. It’s the basic concept behind the entire electric fence system. Joule is the energy used to deliver current in the fence wires.

What is a Joule?

A joule is the SI unit of energy. It is used when one Newton force is applied to move an object one meter. For example, lifting a ball weighing one Newton to one meter uses 1 joule of energy.

In electrical terms, one joule is the energy released in a second when one ampere of current passes through a conductor with one-ohm resistance. According to Joule’s Law, the heat (or joules) produced in a circuit is directly proportional to the current, resistance, and time.

Joules in Electric Fences

Fence energizers are rated in joules, which is the energy required to deliver voltage through the fence wires. The higher the joule rating, the more powerful the fence energizer.

For example, think of joules like calories. Carrying a 5 kg weight for 1 km burns a certain number of calories. Increasing the weight to 10 kg requires more calories. Similarly, if there is less load on the fence, fewer joules are needed. More joules are required for more vegetation, dry ground, or poor conductors.

Recommended Joules for an Electric Fence

The recommended joules requirement is at least one joule per mile. However, delivering more joules makes your fence more effective. Ideal conditions require fewer joules, but factors like vegetation, dry soil, and poor conductors increase the need for more joules.

Increasing Joules in a Fence Charger

To increase joules in your fence charger, you can:

Reduce vegetation around the fence.

Use an AC-powered fence charger.

Use high-quality conductors in the fence wires and ground rods.

Keep the soil moist.

Resolve any short circuits.

Making it easier for the current to move through the fence requires fewer joules, saving power consumption.

Factors Impacting Joules/power in a Fence

Length of Wires: Measure the area where you’ll install electric fence wires. Multiply the length by the number of wires. For longer fences, use a charger that outputs more joules. For example, a fence with 5 wires covering 2 miles requires a charger that outputs at least 10 joules.

Grounding/Earthing: For each joule output, you’ll need 3 feet of ground rods. For a 10-joule fence energizer, you’ll need 30 feet of ground rods. Dry soil has low conductivity, requiring more ground rods to maintain a steady charge.

AC vs. DC Fence Chargers: AC-powered fence chargers can output more joules, while DC (battery-based) or solar chargers have limited current supply.

Type of Animals: Different animals require different joules. For instance, animals with thick fur like sheep need more joules to deliver a shock.

Quality of Conductors: Using good conductors with minimal resistance helps deliver voltage efficiently, requiring fewer joules.

Stored vs. Output Joules: Stored joules are the energy saved in the energizer’s capacitor, while output joules are the energy sent through the fence wires. Output joules are usually 30–40% lower than stored joules due to inefficiencies in the transformer.

How Fence Chargers Work

Capacitors in the charger store current and discharge it to a transformer, which converts low voltage, high amperage current to high voltage, low amperage current and pushes it into the fence wires. Always check the output joule rating before buying a fence charger to ensure it meets your needs.

Frequently Asked Questions

How many joules for cattle?

For cattle, maintain at least one joule per mile. Animals with thick fur like sheep require 3–6 joules per mile.

2. How many joules for a dog fence?

Dog fences should have one joule per mile. Ensure there are no gaps for dogs to escape and place the electrified wires at nose height.

3. How many joules for a bear fence?

Bear fences require at least 0.7–1 joule per mile. Baiting the live wire with honey or peanut butter can help deliver a memorable shock.

4. How many joules for a horse fence?

For horses, maintain at least one joule per mile. Install at least 5-foot high fences as horses can jump high.

Conclusion

In summary, a joule is the energy used to deliver current in an electric fence. Ideal conditions require fewer joules, but factors like vegetation, dry soil, and poor conductors increase the need for more joules.

To maintain a powerful charge in your fence, ensure you have at least one joule per mile. If you have any questions about joules in an electric fence, feel free to ask in the comments below.

Reference: https://fencefacts.com/joule-in-electric-fence/

[redwaypower06]

The 36V 80Ah lithium battery from Redway Power™ is an exceptional energy storage solution, particularly tailored for golf carts, and engineered with LiFePO4 technology for enhanced performance and longevity. This battery stands out with its ability to support up to 4000 cycles, a significant advantage over traditional lead-acid batteries, leading to lower costs over its service life. The 36V 80Ah lithium battery delivers a continuous output of 8 Amperes for 10 hours, providing a total energy capacity of 2,880 Watt-hours. Its design is not only robust but also lightweight and compact, making it ideal for integrating into electric vehicles and various other applications that require a dependable power source.

The versatility of this 36V 80Ah lithium battery makes it suitable for a range of uses beyond golf carts, including marine applications where the 36V lithium ion marine battery is valued for its performance in harsh environments. The 36V lithium battery is also a popular choice for solar energy storage, offering efficient energy management and backup power support during outages. The 36V lithium ion battery’s high energy density and low self-discharge rate contribute to its appeal for portable power solutions and renewable energy systems.

For seamless integration and upgrade, the 36V lithium battery charger and 36V lithium battery pack from Redway Power™ provide a comprehensive solution for maintaining and enhancing the performance of electric vehicles and other equipment. The golf cart 36v lithium battery conversion kit simplifies the transition to a more efficient and eco-friendly power source, making it an accessible option for those looking to upgrade their golf carts or other vehicles.

In summary, the 36V 80Ah lithium battery from Redway Power™ is a reliable and efficient energy storage solution, offering a long cycle life, high energy density, and versatile application. Whether used in golf carts, marine vessels, solar energy systems, or as part of a backup power setup, this battery delivers consistent and reliable power supply, making it a preferred choice for both commercial and recreational applications.

[prestotesting]

How to Perform a Dart Impact Test on Plastic Films: A Step-by-Step Guide

A dart impact test is a method to measure the impact resistance of plastic films and laminates by dropping a dart on them from a certain height. The test can help evaluate the quality, durability, and performance of various plastic products and materials. The test can also help compare the effectiveness of different surface treatments, such as electroplating, galvanizing, painting, etc. The test is standardized by several national and international standards, such as ASTM B117, ISO 9227, JIS Z 2371, and ASTM G85.

To perform a dart impact test on plastic films, you will need a dart impact tester, a sample holder, a scale, a release mechanism, and a sample of the material to be tested. You can find some examples of dart impact tester online, such as Presto Group or Amazon. You can also compare the prices, features, and specifications of different models and brands and choose the one that suits your needs and budget.

Here are some steps that you can follow to perform a dart impact test on plastic films:

1. Prepare the sample of the material to be tested according to the standards and specifications. The sample should be large enough to extend beyond the sample holder by at least 25 mm at all points. The sample should also be representative of the material under study and should be taken from the sheet or tube in such a manner that the whole of the sheet is represented in the test. You can use a template to guide the cutting of the sample and a thickness gauge to measure the thickness of the sample.

2. Clamp the sample in the sample holder and connect the pneumatic pipe to the vacuum pump. Turn on the vacuum pump to hold the sample securely and prevent any air pockets. The sample should be clamped by the specimen holder ring and should have a slit that allows the dart to pass through and tear the sample.

3. Adjust the level of the machine with the spirit level and lock the leveling bolts in the proper position. Ensure that the apparatus does not vibrate and has a proper earthing connection. Connect the power supply cord of the device to a 3-pin 5-ampere socket on a single-phase 230 V AC supply line.

4. Choose the appropriate weight of the dart that is nearest to the expected impact failure weight. You can also add the required number of incremental weights to the dart shaft and put the locking collar in its place to set the weights in a particular location.

5. Adjust the height of the drop of the dart according to the standards and application requirements. You can use the release mechanism of the vertical channel support to set the height of the drop. The dropping height of the dart can be 660 mm or 1524 mm, depending on the type of test.

6. Place the dart in the release mechanism and align it with the center of the sample. Make sure that the dart is free from any dirt or dust and has a smooth surface.

7. Release the dart from the starting position by using the trigger or the button of the release mechanism. The dart will fall freely and hit the sample, causing it to tear. The force and the distance of the tear will be recorded by the scale and the display of the device.

8. Remove the sample from the sample holder and examine the damage caused by the dart. You can use a marker to record the maximum force reached by the pointer and the scale. You can also use a ruler to measure the length of the tear.

9. Calculate the Falling dart impact tester of the material by using the formula: Dart impact strength = Weight of the dart in grams / 10 min. You can also use a computer interface or software to generate graphical and numerical reports of the test results.

10. Repeat the test with different samples and weights of the dart to obtain an average value of the dart impact strength of the material.

I hope this guide helps you to perform a dart impact test on plastic films.

[ipesrltechnologies]

Choose the Right Battery for Your UPS from Top Suppliers

Uninterruptible Power Supplies (UPS) are essential for safeguarding critical electronic equipment from power interruptions and surges. However, the effectiveness of a UPS system heavily relies on the type and quality of the battery it uses. Selecting the right batterie per UPS is crucial to ensure uninterrupted power backup when you need it most.

UPS systems typically use two main types of batteries: Valve-Regulated Lead-Acid (VRLA) batteries and Lithium-ion (Li-ion) batteries. VRLA batteries are cost-effective and require minimal maintenance, making them suitable for smaller setups. Li-ion batteries, on the other hand, offer longer lifespans, higher energy density, and faster recharge times, making them ideal for larger and more demanding applications.

The battery's capacity, measured in ampere-hours (Ah) or watt-hours (Wh), determines how long your UPS can provide backup power. Calculate your load requirements to determine the appropriate battery capacity and runtime needed during power outages.

Consider the maintenance requirements of the batterie per UPS. VRLA batteries are typically maintenance-free, while Li-ion batteries may require occasional monitoring and maintenance.

Battery lifespan is crucial. VRLA batteries last around 3-5 years, whereas Li-ion batteries can last up to 10 years or more. Factor this into your total cost of ownership.

Ensure the battery you choose is compatible with your UPS model. Different UPS units have specific requirements for battery voltage and size.

Selecting the right batterie per UPS is essential for reliable backup power. Assess your needs, budget, and the UPS model you own to make an informed decision. Investing in a high-quality battery will provide peace of mind during unexpected power disruptions, keeping your critical equipment safe and operational.

[esennartransformer]

How to Determine the Right Transformer Size for Your Electrical Application?

Transformers play a vital role in electrical systems by enabling the efficient transmission and distribution of electrical power. However, selecting the correct transformer size is crucial to ensure that your electrical application operates efficiently, safely, and cost-effectively. In this guide, we'll walk you through the steps to determine the right transformer size for your specific needs.

Understanding Transformer Basics

Before diving into the details of transformer sizing, it's essential to understand the fundamental principles and components of transformers. A transformer is an electrical device that transfers electrical energy between two or more circuits through electromagnetic induction. The key components of a transformer include the core, primary winding, and secondary winding.

Transformers work on the principle of electromagnetic induction. When alternating current (AC) flows through the primary winding, it generates a magnetic field in the core, which, in turn, induces a voltage in the secondary winding. This allows transformers to either increase (step-up) or decrease (step-down) voltage levels while maintaining the frequency of the alternating current.

Factors Influencing Transformer Sizing

Several factors influence the size of the transformer required for a specific application:

Load Characteristics: Understanding your electrical load is critical. This includes assessing the peak load, average load, and any load fluctuations that may occur. Accurate load analysis is essential to correctly size the transformer.

Power Factor: The power factor is a measure of how effectively electrical power is being converted into useful work output. It can significantly impact the size of the transformer. A low power factor indicates that the load is less efficient in utilizing the electrical power supplied.

Voltage Requirements: Consider the required voltage levels for your application. Transformers are often used to step up or step down voltage, depending on the specific needs of your electrical system.

Load Analysis

Conducting a thorough load analysis is a crucial step in determining the right transformer size for your application. This analysis involves collecting data on the magnitude and characteristics of your electrical load. It's essential to assess the load profile over time, taking into account fluctuations and any future load growth.

Transformer Sizing Calculations

Once you have gathered data on your load, you can begin the transformer sizing calculations. The primary parameter used to size transformers is the kVA (kilovolt-ampere) rating, which is a measure of apparent power. Here's how you can calculate the kVA rating needed:

Calculate the Active Power (kW): Determine the active power (in kilowatts) that your load requires. This is often specified in your electrical plans or can be calculated based on your load analysis.

Calculate the Apparent Power (kVA): The apparent power is calculated by dividing the active power (kW) by the power factor. The formula is: Apparent Power (kVA) = Active Power (kW) / Power Factor

Consider Efficiency: To ensure that the transformer operates efficiently, you may need to account for transformer losses by adding a margin to the calculated kVA rating. This margin typically ranges from 10% to 25%.

Choose a Standard kVA Rating: Transformers are available in standard kVA ratings. Round up your calculated kVA rating to the nearest standard size.

Overhead vs. Underground Transformers

Depending on your application's specific requirements, you may need to choose between overhead and underground transformers. Each option has its advantages and disadvantages.

Overhead Transformers are mounted on utility poles and are visible. They are often chosen for their ease of installation and maintenance. However, they may be less aesthetically pleasing and are exposed to environmental elements.

Underground Transformers are placed in underground vaults, providing a neater appearance. They are protected from weather conditions and vandalism. However, they require more complex installation and maintenance procedures.

The choice between overhead and underground transformers should be based on factors such as available space, aesthetics, and long-term maintenance considerations.

Selecting the Right Transformer Type

Transformers come in various types, including distribution transformers, power transformers, and special-purpose transformers. Your choice should align with your application's specific needs.

Distribution Transformers are commonly used for local power distribution in residential and commercial areas.

Power Transformers are designed for high voltage transmission and are often found in substations.

Special-Purpose Transformers are tailored for specific applications, such as rectifier transformers for industrial processes or furnace transformers for melting operations.

Consider the unique requirements of your application to determine the most suitable transformer type.

Consulting with Experts

Finally, it's important to note that selecting the right transformer size is a critical decision that can impact the safety and efficiency of your electrical system. Consulting with electrical engineers or transformer manufacturers can provide valuable insights and expertise to ensure that your selection is accurate and meets all safety and performance standards.

In conclusion, selecting the right transformer size for your specific application requires a thorough understanding of your load, power factor, voltage requirements, and other critical factors. By following the steps outlined in this guide and seeking expert advice when needed, you can make an informed choice that ensures the efficient and reliable operation of your electrical system.

[onlineupsprice15]

In today’s technology-driven world, ensuring uninterrupted power supply is critical for businesses. A single power outage can disrupt operations, cause data loss, and negatively impact customer experience. To combat these challenges, Vertiv 10 kVA Online UPS, offered by Online UPS Price, provides reliable, robust, and cost-effective power solutions tailored to meet diverse business needs. In this blog, we’ll explore why this UPS system is a game-changer for enterprises, especially those looking for dependable power protection.

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An Online UPS (Uninterruptible Power Supply) is a type of UPS system that continuously provides clean, uninterrupted power to connected devices by converting incoming AC power into DC power, storing it in a battery, and then converting it back to AC before distributing it. This double conversion process ensures that the load is isolated from all power issues, including voltage spikes, frequency variations, and surges. When it comes to protecting critical equipment, an online UPS like Vertiv 10 kVA stands out as a top choice. “Vertiv 10 kVA Online UPS”

Why Choose Vertiv 10 kVA Online UPS?

High Capacity and Scalability The Vertiv 10 kVA UPS is designed for environments that demand high power capacity. With its 10 kVA (Kilovolt-Ampere) rating, it is ideal for small to medium-sized businesses, data centers, IT equipment, and telecom infrastructure. Moreover, it is scalable, meaning you can expand the system as your power needs grow, ensuring long-term protection.

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Energy Efficiency Vertiv has always been known for its focus on energy-efficient designs. The 10 kVA model is no exception, offering high efficiency even at partial loads, which helps reduce operating costs. This energy efficiency also contributes to a smaller carbon footprint, aligning with eco-friendly business practices.

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Advanced Monitoring and Management One of the standout features of this UPS is its advanced monitoring and management capabilities. Vertiv's solutions come with an intuitive LCD interface and remote management options. You can monitor real-time power conditions, check battery health, and receive alerts on potential issues, all from a user-friendly dashboard.

Cost-Effective Power Solution While the market is flooded with various UPS systems, Vertiv 10 kVA stands out for its cost-effectiveness. Thanks to the quality, scalability, and longevity of the product, it proves to be an excellent investment for businesses. Additionally, with Online UPS Price, you are guaranteed competitive pricing, ensuring you get the best value for your money. “Vertiv 10 kVA Online UPS”

Applications of Vertiv 10 kVA Online UPS

The Vertiv 10 kVA UPS is versatile and can be used across a variety of industries and applications:

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Healthcare: Ensuring medical equipment remains operational during power outages.

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Manufacturing: Keeping production lines running smoothly by avoiding power interruptions.

Why Buy from Online UPS Price?

As a trusted supplier of uninterruptible power systems, Online UPS Price provides customers with high-quality power solutions at competitive rates. With a focus on customer satisfaction, they offer:

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Conclusion

In a world where power reliability is paramount, investing in a Vertiv 10 kVA Online UPS from Online UPS Price is a smart decision for any business. With its cutting-edge features, energy efficiency, scalability, and robust battery backup, the Vertiv UPS provides reliable protection for mission-critical operations. Whether you're managing a data center, safeguarding healthcare equipment, or protecting financial transactions, this UPS ensures business continuity and peace of mind.

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[baliportalnews]

PLN Siapkan Sistem Listrik Hijau dan Canggih untuk Istana Kepresidenan di IKN

BALIPORTALNEWS.COM, JAKARTA - PT PLN (Persero) akan menyiapkan sistem kelistrikan yang andal untuk Istana Kepresidenan di Ibu Kota Negara (IKN) Nusantara. Sistem kelistrikan ini mengusung konsep state of the art of technology dengan berbasis pada pasokan listrik ramah lingkungan, indah dan didukung oleh teknologi pintar. Sistem serupa telah diterapkan PLN dalam revitalisasi kelistrikan di Istana Kepresidenan Jakarta pada Selasa (1/8/2023). Revitalisasi ini akan membuat sistem kelistrikan di Istana Kepresidenan menjadi tempat yang paling andal di seluruh Indonesia. Direktur Utama PLN, Darmawan Prasodjo mengungkapkan, revitalisasi kelistrikan yang telah dilakukan PLN di Istana Kepresidenan Jakarta merupakan tahapan untuk membangun sistem kelistrikan yang lebih andal di IKN. Untuk pembangunan sistem kelistrikan IKN, PLN menganut prinsip Green, Beautiful dan Smart berbasis Artificial Intelligence (AI). "Revitalisasi kelistrikan Istana ini ibaratnya adalah prototipe bagi kami untuk membangun sistem kelistrikan yang lebih besar lagi, yaitu sistem kelistrikan di IKN," jelasnya. PLN menyiapkan sistem kelistrikan modern yang terintegrasi untuk menjamin listrik yang andal tanpa kedip. Listrik untuk istana akan disuplai dari 4 gardu induk yang dibackup genset dengan kapasitas 4 x 2.000 kilovolt ampere (kVA) dan Uninterruptible Power Supply (UPS) 8 x 400 kVA yang dapat beroperasi terus menerus. Sedangkan untuk menjaga keindahan, peralatan yang berupa trafo, UPS serta genset akan ditanam di dalam tanah dengan kedalaman kurang lebih 10 meter, dan seluruh peralatan tersebut terjamin keamananya. Selanjutnya, untuk penataan kabel akan dilakukan dengan menggunakan jaringan kabel bawah tanah, sehingga menjaga keindahan dengan tanpa adanya kabel di udara. "Kami ingin sistem kelistrikan Istana Kepresidenan di IKN seperti kondisi kelistrikan Istana Jakarta yang sudah jauh lebih andal, lebih kokoh, dan lebih modern. Menggunakan state of the art of technology, sistem ini adalah yang tercanggih se-Indonesia bahkan Asia Tenggara," ujar Darmawan. Selain itu, PLN juga siap membangun Smartgrid yang terintegrasi dengan Control Center, dan Advanced Meter Infrastructure (AMI) untuk menghubungkan sistem kelistrikan Istana Kepresidenan IKN dengan sumber-sumber energi baru terbarukan (EBT). Sementara ini pasokan listrik IKN akan ditopang oleh Pembangkit Listrik Tenaga Surya (PLTS) yang tersebar sebesar 50 megawatt (MW) dan tambahan Pembangkit Listrik Tenaga Air (PLTA). Kemudian untuk mewujudkan sarana transportasi yang ramah lingkungan, PLN akan membangun infrastruktur kendaraan listrik yang menjangkau seluruh wilayah IKN. Tidak hanya itu, PLN juga mendukung bidang pendidikan di kawasan IKN dengan membangun sekolah vokasi IT PLN. "Segala konsep pembangunan telah dikomunikasikan dengan baik oleh PLN kepada stakeholder terkait. Ini adalah komitmen kita bersama, khususnya PLN, untuk membangun sistem kelistrikan yang Green, Beautiful dan Smart untuk Istana Kepresidenan di ibu kota baru," tutup Darmawan. Ke depan, konsep kelistrikan seperti ini juga akan diterapkan juga di tempat-tempat penting dan strategis lainnya di kota-kota atau di setiap tempat penting di Indonesia.(bpn) Read the full article

[teardownit]

PWM LED dimmer

Let's build a fully analog PWM LED dimmer on four operational amplifiers and learn what PWM is used for and what it actually is.

As most of us already know, the brightness of the LED depends on the current flowing through it, while the voltage on the LED stays nearly the same when the current changes.

To set the current, in the simplest case with a constant supply voltage, one includes a resistor in series with the LED.

Then, the voltage of the power supply will be equal to the sum of the operating voltage of the LED, which can be considered constant, and the voltage drops across the resistor.

According to Ohm's law, the voltage drop across a resistor is its resistance times the current.

According to the Joule-Lenz law, the DC power equals the voltage times the current.

Suppose we have a powerful white LED with an operating voltage of 3 volts and an operating current of 1 ampere. And we power it from a source with a voltage of 4 volts.

In this case, at a current of 1 A, we have a 1-ohm resistor. It drops 1 volt and generates 1 watt of heat. This is quite high power; a high-power resistor would be needed.

The LED gets 3 watts out of a total power consumption of 4 watts. The efficiency of such a flashlight is 3/4 = 75%, not considering the energy lost to heat the LED or the internal resistance of the battery.

If one takes a 2-ohm resistor, the voltage drop across it will remain at 1 volt because 4 volts of power supply minus 3 volts for the LED equals 1 volt.

The current, in this case, will be 0.5 amperes, the power consumption of the LED will be 1.5 watts, and the losses on the resistor will be 0.5 watts.

The efficiency remains the same. It is equal to the ratio of the operating voltage of the LED to the supply voltage.

To adjust the LED current, one can use a potentiometer. But a variable resistor with a power rating of 1 watt is quite a rare thing. To change the brightness of the LED with a low-power potentiometer, we can use a transistor-based current source.

Let's hook up a high-power transistor into the circuit with a common collector called an emitter repeater. The voltage across the current-limiting shunt will equal the voltage across the base minus the Ube of the transistor.

The voltage Ube between the base and emitter can be considered a constant value. It can be in the range of 0.6 to 0.8 volts, and basically, it can be equated to the forward voltage drop across a silicon diode. After all, the two P-N junctions of the transistor are essentially diodes.

Considering the Ube of the transistor Q1 is equal to the forward drop on the diode D2 and equal to 0.65 volts, the voltage across the series-connected R2 and RV1 will be 4 minus 0.65 = 3.35 volts. The current, through their total resistance of 335 ohms, will equal 10 milliamperes.

Let's say that the current gain of our transistor is greater than 400. Then, at a collector current of 1A, the base current will be less than 2.5 milliamps. For the sake of simplicity, we'll neglect this current. However, it is a quarter of 10 mA current through potentiometer RV1 and limiting resistor R2.

Because we have compensated Ube by the drop across diode D2, the emitter follower works so that the voltage across shunt R1 will equal the voltage between anode D2 and brush RV1.

In the lowest position of RV1 in the diagram, the voltage across the shunt and, consequently, the emitter current of the transistor and the LED current will be zero.

In the top-most position, the voltage will be 3350 × 15 / (320 + 15) = 150 millivolts. In this case, the current through R1 with a resistance of 150 milliohms will equal 1 ampere. So, we got ourselves a smooth adjustment of the LED brightness with a low-power potentiometer and a powerful transistor.

The heat generation of RV1 will be 150 mV × 10 mA = 1.5 milliwatts.

If we consider the base current of the transistor equal to 2.5 mA, then R2 should have a voltage drop of 3.2 V at a current of 12.5 mA instead of 10 mA. This means the resistance of R2 should be 3200 / 12.5 = 256 ohms.

The scheme I have drawn up is good for illustration purposes rather than practical application. There is too much instability and dependence on the parameters of specific components.

There is a probability that the LED current will exceed its rating of 1 ampere and burn out. Or vice versa, the current and, therefore, the brightness will be too low. And we have not accounted for the fact that as the battery discharges, its voltage drops, especially under load.

In the past, electronic DIY devices and even mass-manufactured ones had to be tuned by hand-picking compatible components before packaging them for sale, just like this circuit. That's because electronic components were expensive, inaccurate, and unstable.

Today, components are much more advanced and affordable, and they can be used to create a circuit that is stable and doesn't require meddling.

To eliminate the need to consider the base-emitter voltage of the transistor, let's use an operational amplifier.

An ideal operational amplifier is described by two statements. First, its input impedance is huge, and virtually no current flows through its inputs.

Second, an operational amplifier will set the output voltage such that the voltages at the inverting and non-inverting inputs are equal. (Through a feedback loop from the output to the inverting input.)

Here, the operational amplifier is connected as a voltage follower. And it is not an emitter follower but a full-fledged follower. The voltage on the shunt R1 will go to the inverting input and is thus almost precisely (with a difference of no more than 3 millivolts, most often about 300 microvolts) equal to the voltage on the non-inverting input, which is set by the knob of the potentiometer RV1.

The precision voltage reference TL431 is used to stabilize the voltage on the potentiometer. The voltage at the cathode U2, and consequently at the divider R3 RV1, is 2.5 volts. Of this, the potentiometer gets 1/25 = 100 millivolts.

That means we can adjust the voltage at the 100 milliohm shunt R1 from 0 to 100 millivolts, and thus the current from 0 to 1 amp.

Congratulations! We have built an LED brightness regulator with a stabilized current that does not depend on the supply voltage, i.e., the battery charge percentage.

The efficiency of the transistor regulator is still the ratio of the LED operating voltage to the supply voltage. In this case, the same 75%, minus tiny losses to power auxiliary circuits.

At maximum operating current on the current limiting resistor (shunt), it dissipates just 0.1 watts of heat. In contrast, on the transistor (which is easy to equip with a heat sink), it dissipates the remaining 0.9 watts.

If only we had a current stabilizer with a pulse energy converter, as in the post about a boost LED driver, we could significantly increase the efficiency!

The pulse stabilizer's shunt resistance can be even more minor—tens or even single milliohms. The resistance of the MOSFET in an open state can be the same.

On the other hand, other energy losses characteristic of pulse converters are added, mainly for remagnetizing the core of the inductor coil and for the ESR of the output electrolytic capacitor. So we need a good coil and a good cap.

Pulse width modulation, which is also used in switching power supplies, does not regulate the current amplitude. Instead, it interrupts the current several hundred, thousand, or more times per second.

By interrupting the current, electrical charge and power are reduced compared to the always-on state. At the same time, the transistor is operating in key mode, so the voltage drops across, and the heat losses are minimal.

This is one of many advantages of PWM over linear control. The microcontroller needs a digital-to-analog converter (DAC) to output the control voltage. And it is much easier for the microcontroller to output the time intervals that define the on and off states and to generate pulses to turn on the transistor.

When adjusting the brightness of LEDs, PWM may have a disadvantage: flickering can be heavy on the eyes, cause fatigue, and, in industrial environments, even lead to fatal accidents.

This can happen due to the stroboscopic effect; rotating machinery parts may appear slower, stationary, or spinning in the opposite direction. Together with flicker fatigue, this can create a dangerous premise.

Therefore, the questions of the overall quality of LED lighting, its energy and cost efficiency, and the extension of the service life of LEDs remain open.

PWM is most often implemented on special analog IC controllers as well as on microcontrollers using digital counters and timers. And today, we will look closely at and test a classic circuit on three operational amplifiers (plus one buffer).

A relaxation oscillator, or multivibrator, is assembled on U1A and U1B. Its feature is that the timing capacitor C1 is included in the negative feedback loop of the operational amplifier U1B. Because of this, the voltage at the output of U1B varies linearly, and we have an almost perfect triangular waveform.

U1A is used as a comparator with hysteresis (a positive feedback loop through resistor R9). The voltage at the inverting input is always zero because it is connected to the circuit ground. (Note that the power supply is bipolar: +12 and -12 volts.) This is uncommon for real LED dimmers, but a board we have is for educational experiments.

When a positive voltage appears at the non-inverting input U1A, the comparator output switches to the high logic level state (plus supply minus the voltage drop across the chip's output transistors).

Conversely, when the voltage at the non-inverting input U1A becomes negative, the comparator switches to a low logic level state.

Resistor R8 and two counter-sequential Zener diodes, D1 and D2, form a simple parametric voltage-limiting stabilizer. It is +6 volts at the high level and -6 volts at the low level.

This is how rectangular pulses of a given amplitude with a frequency of 859 hertz and a duty cycle of exactly 50% are obtained because the circuit is symmetrical: the time-delay capacitor is charged and then discharged through the same circuit, and the absolute value of the positive voltage is equal to the absolute value of the negative voltage.

Accordingly, the triangular waveform is also wholly symmetrical. The oscilloscope shows a fill factor of 50%.

U2A is used simply as a voltage repeater buffer, and strictly speaking, it is optional because operational amplifiers have a high input impedance.

U2B is a PWM comparator. It will switch high when the instantaneous value of the triangular waveform voltage from U1B is lower than the voltage set by potentiometer RV1. In this way, the potentiometer adjusts the fill factor.

Note that when the duty cycle is low, the voltage at the output of U2B does not reach its maximum. This is because the edges of the pulses are not exactly vertical. The output voltage rises, and falls are not instant. An operational amplifier has a slew rate parameter, and the LM358 has a rather low one.

Next, a push-pull amplifier with three transistors is connected, and the signal from its output controls the stage on transistor Q4, which interrupts the LED current. In the video, we can see how it all works.

Thanks for your attention!