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Phone power supply device. How to convert a cell phone charger to a different voltage

Any person at least once in his life has encountered the battery of an urgently needed electronic device that was discharged at the wrong time, and many of us experience this kind of trouble regularly.

The way to solve the problem is simple - you just need to get a compact external battery, recharge it in a timely manner and don’t forget it at home when going on business. We offer you a rating of the best external batteries of 2018 - the first half of 2019, based on reviews from experts and ordinary buyers. Just don’t forget - to choose the best external battery, you need to realistically assess your needs and choose a device with optimal capacity. As a first approximation, its value should be twice as high as the corresponding battery indicator of the gadget that is supposed to be charged most often.

External battery capacity - what does it mean?

When indicating the rated capacity for their external batteries, manufacturers write the truth, but not the whole truth. For example, the 13,000 mAh declared for the Canyon CNE-CPB130 actually has a built-in battery. Only you can fully charge a smartphone with a 4,000 mAh battery with such a power bank only twice. The fact is that the nominal capacity here means the energy reserve accumulated by the device’s battery at its operating voltage. In this case, it is approximately 3.7 volts, which is noticeably lower than the value defined by the USB specification. And to the extent that mobile equipment has to be charged through this particular interface, the internal voltage is converted to standard 5 V with a proportional decrease in the available capacity. In addition, part of the energy is spent on the operation of the corresponding electronic circuit. For reference, current external batteries use lithium-ion (3.6-3.7 V) or lithium-polymer (3.85 V) batteries, and the efficiency of the converters ranges from 0.9 to 0.95.

Thus, knowing the “capacity” of the batteries of a power bank and a smartphone, it is easy to calculate how many times you can charge the second device with the first device. To do this, the nameplate value of the capacity of the external battery must be multiplied by the operating voltage of its own battery (if the type is unknown, take 3.6 V), divide by 5 volts of the USB interface, and multiply the result by the efficiency (set to 0.9). As a result, we will get the useful capacity of the device, which can be used when charging.

To complete our example, we have (13000 * 3.7 / 5) * 0.9 = 8658 mAh, which is enough for two full charges of, say, Xiaomi Redmi 4X with its 4,100 mAh battery. And there will still be a little left “in reserve.”

2 590 ₽

Show phone

Ring-shaped LED lamp + tripod. New. There is a guarantee and delivery in Moscow.

A very useful tool that will be useful to everyone!

For a makeup artist or lash maker (eyelash extension specialist), beauty salons: The lamp provides uniform illumination and full visibility. The light of the ring lamp emphasizes the texture of the skin and perfectly conveys the shades of makeup and hair color.

For a blogger or photographer: with this lamp you can take cool selfie photos, stream, record videos for a video blog or Instagram. The lamp provides high-quality, professional lighting and is unusually reflected in the eyes

As an unusual element of the interior, a round lamp: in addition to its main professional functions, such a lamp also looks great as an original lamp for the home or beauty salon.

Control:
1. Adjusting the color temperature will allow you to choose the right type of light for a specific photo or makeup color
2. By adjusting the brightness you can select the desired power without moving the lamp
3. Possibility of adjusting the tilt of the lamp by 90 degrees and the height of the tripod up to 2 meters

The kit includes:
1. Light ring
2. Mains power supply
2. Tripod 2 meters
3. Phone holder
4. Bag case (for 35 cm lamp)
5. Remote control (for 32cm lamp)

Characteristics:
Power: 48W, From 180 to 480 LEDs. Diode lifespan 50,000 hours
External diameter: from 20 to 46cm
Weight: from 1.8 to 3.6 kg.

Lamp sizes:
1) diameter 25 cm + tripod. USB powered (can be taken outdoors and turned on from a power bank)
2) diameter 32 cm + tripod (control from a wireless remote control, powered from an outlet)
3) diameter 35 cm + tripod + bag-case, powered from an outlet (this lamp is not only larger in diameter, but also more powerful - it has two rings of LEDs)
4) diameter 50 cm + tripod + smartphone mount + bag - ideal for professional studios and anyone who needs the most powerful bright light

Bluetooth remote control for an additional fee - 190 rubles (controls the phone. With its help, you do not need to hold it in your hands or reach for the phone)

Also, you can purchase ring lamps wholesale from us.

Delivery in Moscow - TODAY, by courier to the address
- Pickup - showroom in the very center of the city, near Lubyanka metro station
- Delivery to regions Avito-Delivery
- Warranty for all goods

Greetings radio amateurs!!!
While going through old boards I came across a couple of switching power supplies from mobile phones and wanted to restore them and at the same time tell you about their most common breakdowns and elimination of shortcomings. The photo shows two universal schemes for such charges, which are most often found:

In my case, the board was similar to the first circuit, but without an LED at the output, which only serves as an indicator of the presence of voltage at the output of the block. First of all, you need to deal with the breakdown; in the photo below I outline which parts most often fail:

And we will check all the necessary details using a conventional DT9208A multimeter.
It has everything you need for this. A mode for testing diodes and transistor junctions, as well as an ohmmeter and a capacitor capacitance meter up to 200 µF. This set of functions is more than enough.

When checking radio components, you need to know the base of all parts of transistors and diodes, especially.

Now all cell phone manufacturers have agreed and everything that is in stores is charged via a USB connector. This is very good because chargers have become universal. In principle, a cell phone charger is not such a thing.

This is only a pulsed direct current source with a voltage of 5V, and the charger itself, that is, the circuit that monitors the battery charge and ensures its charge, is located in the cell phone itself. But that’s not the point, the point is that these “chargers” are now sold everywhere and are already so cheap that the issue of repairs somehow disappears by itself.

For example, in a store “charging” costs from 200 rubles, and on the well-known Aliexpress there are offers from 60 rubles (including delivery).

Schematic diagram

A typical Chinese charging circuit, copied from the board, is shown in Fig. 1. There may be an option with swapping diodes VD1, VD3 and zener diode VD4 to the negative circuit - Fig. 2.

And more “advanced” options may have rectifier bridges at the input and output. There may also be differences in part ratings. By the way, the numbering on the diagrams is given arbitrarily. But this does not change the essence of the matter.

Rice. 1. Typical circuit diagram of a Chinese network charger for a cell phone.

Despite its simplicity, this is still a good switching power supply, and even a stabilized one, which is quite suitable for powering something other than a cell phone charger.

Rice. 2. Circuit diagram of a network charger for a cell phone with a changed position of the diode and zener diode.

The circuit is made on the basis of a high-voltage blocking generator, the width of the generation pulses is regulated using an optocoupler, the LED of which receives voltage from the secondary rectifier. The optocoupler reduces the bias voltage based on the key transistor VT1, which is set by resistors R1 and R2.

The load of transistor VT1 is the primary winding of transformer T1. The secondary, step-down winding is winding 2, from which the output voltage is removed. There is also winding 3, it serves both to create positive feedback for generation, and as a source of negative voltage, which is made on diode VD2 and capacitor C3.

This negative voltage source is needed to reduce the voltage at the base of transistor VT1 when optocoupler U1 opens. The stabilization element that determines the output voltage is the zener diode VD4.

Its stabilization voltage is such that, in combination with the direct voltage of the IR LED of the optocoupler U1, it gives exactly the necessary 5V that is required. As soon as the voltage at C4 exceeds 5V, the zener diode VD4 opens and current flows through it to the optocoupler LED.

And so, the operation of the device does not raise any questions. But what if I need not 5V, but, for example, 9V or even 12V? This question arose along with the desire to organize a network power supply for a multimeter. As you know, multimeters, popular in amateur radio circles, are powered by Krona, a compact 9V battery.

And in “field” conditions this is quite convenient, but in home or laboratory conditions I would like power from the mains. According to the diagram, “charging” from a cell phone is in principle suitable, it has a transformer, and the secondary circuit is not in contact with the electrical network. The only problem is the supply voltage - “charging” produces 5V, but the multimeter needs 9V.

In fact, the problem of increasing the output voltage is solved very simply. You just need to replace the zener diode VD4. To obtain a voltage suitable for powering a multimeter, you need to set the zener diode to a standard voltage of 7.5V or 8.2V. In this case, the output voltage will be, in the first case, about 8.6V, and in the second about 9.3V, which, both of them, are quite suitable for a multimeter. Zener diode, for example, 1N4737 (this is at 7.5V) or 1N4738 (this is at 8.2V).

However, you can use another low-power zener diode for this voltage.

Tests have shown good performance of the multimeter when powered from such a power source. In addition, we tried an old pocket radio powered by a Krona, and it worked, only interference from the power supply was a slight hindrance. The matter is not limited to 9V voltage at all.

Rice. 3. Voltage regulation unit for converting a Chinese charger.

Do you want 12V? - No problem! We set the zener diode to 11V, for example, 1N4741. You just need to replace capacitor C4 with a higher voltage one, at least 16V. You can get even more tension. If you remove the zener diode altogether, there will be a constant voltage of about 20V, but it will not be stabilized.

You can even make a regulated power supply if you replace the zener diode with a regulated zener diode such as the TL431 (Figure 3). The output voltage can be adjusted, in this case, by variable resistor R4.

Karavkin V. RK-2017-05.

Modern mobile devices and all kinds of gadgets are equipped with many fashionable and useful functions and applications. And the most complex mobile games amaze with their graphics and capabilities. It is thanks to such applications that any smartphone “sits down” almost throughout the day. Therefore, you need to learn how to choose a more powerful one for your phone. Or choose an additional one

The main reasons why you simply need to choose a new charger

So, the phone began to discharge frequently and quickly. First, you need to decide on the root cause, and only then look for the most optimal ways to solve the problem. So what could be the reasons for early discharge?

If the smartphone or tablet is new, the instructions state a certain operating time, but in fact, the device works several times less, then the reason may lie in the settings. As a rule, on the phone itself you can adjust the brightness and energy consumption or disable several applications that drain the charge.

It’s another matter if the smartphone is configured, it worked quite normally for a long time, but over time it began to discharge much faster. Here, most likely, the internal charger or the external battery of the phone is to blame. The only solution is to replace the element. To do this, you can use either a branded battery or a universal analogue.

Types of external batteries

Despite the prevalence of cell phones and smartphones, there are still only three main types of batteries in the world:

  • Lithium-ion. This is perhaps the most common external battery for charging your phone. It has a more optimal balance of durability, safety and energy intensity than other analogues. Also, such elements are endowed with a special “memory effect” and discharge rather slowly. But they age quickly, even with constant use.
  • Nickel-cadmium. They were recognized as the most harmful and were put on the shelf. They were used only in the very first phones due to their low cost. In addition, the higher their energy intensity, the larger their physical size.
  • Lithium polymer. These are cheaper and more advanced external batteries for cell phones. Therefore, such elements have adopted all the positive aspects of the original sample, and also become more environmentally friendly.

Features of operation and operation

A mobile phone is a rather complex and delicate mechanism. And each of its elements has its own characteristics and requires certain operating conditions, including the battery itself. Therefore, there are several rules that you can follow to significantly extend the life of your phone battery:

  • When using, you must strictly follow the operating rules specified by the manufacturer, i.e. do not overheat, do not get wet or overcool.
  • Try to avoid physical damage to the element.
  • External ones cannot stand frequent blows and falls.
  • You should not open the batteries yourself just for fun.
  • The battery should only be replaced and recharged when the device is turned off.
  • It is not recommended to constantly charge the gadget for a long time (more than a day).
  • The more and more often the battery is used, the better.

Myths about mobile batteries

Over the entire period of their existence, mobile phones have practically become overgrown with various fictions and legends that scare naive users. Several of them concern their most important detail.

Parameters to consider when choosing chargers

When choosing an additional external battery for your phone, you should consider many factors (in addition to the manufacturer and quality of materials). As a rule, experts identify several main parameters by which these elements differ. Therefore, knowing these features, you can choose the appropriate option.

  • Capacity of the presented battery. The operating time without additional recharging directly depends on it. As a rule, 4000-6000 mAh is sufficient.
  • Current strength. If the battery is used to power more than just a smartphone, then you need to choose a device with a power of 1-3 A. For a regular phone, a device that produces 1 A is enough.
  • Charging method. It is better to choose a gadget that can be powered from several sources at once: a regular electrical outlet and via a USB connector.
  • Battery indicator. This element is simply necessary in the daily use of smartphones and phones. There are several options for displaying charge: by changing color or numbers. The numerical indicator provides much more accurate information about the condition of the battery, but it also costs much more.
  • Number of ports used. Thrifty and prudent users choose instances with the largest number of them. But, as a rule, the need to charge several devices at the same time is quite rare. Therefore, 2-3 ports are enough.

Several features to pay attention to when choosing batteries

In addition to the basic parameters that you need to pay special attention to, there are several additional qualities. They can significantly facilitate and prolong the operation of the presented gadgets.

It is best to choose an external battery for your phone, on which the power button will not stand out against the background of the body. After all, if you press it accidentally, you can get a rather unpleasant surprise. It would also be useful to have a special flashlight in the device to make it easier to find in the dark.

In order to protect a valuable item from all kinds of dust or water, as well as to protect against small impacts, it is necessary to choose devices with a special case. Such devices will cost a little more, but their service life will obviously be longer.

Fans of modern innovative technologies will appreciate the presence of such features as Wi-Fi and NAS Server. With their help, you can not only easily use and distribute the Internet, but also save various data on a special memory card.

It will be useful for any battery and after all, in the summer we are not always near any power source.

To purchase a high-quality battery that will last long enough, you should approach this issue with all seriousness. Before making your final choice, you need to familiarize yourself with the most common options, compare characteristics and reviews. And only then will it be possible to buy one for the phone.

  1. First of all, this device should be convenient enough, light and compact to fit easily in any bag.
  2. A charger from the same company as the main device will be much better suited than similar analogues. In addition, in this way you can protect yourself from low-quality goods.
  3. It is better to clarify in advance whether a purchase can be returned and under what conditions. The charger may simply not fit.

Comparison of the most common external batteries

There are many external telephone batteries available. There are probably as many of them as there are mobile devices themselves. In this case, everyone chooses their own external battery for their phone. Reviews are what attention is paid to first. Therefore, here are some subjective opinions about the most popular models:

  • Mini vampire. There is a standard USB connector. Convenient to adjust current and voltage. Among the disadvantages is low efficiency.
  • Boost stabilizer. This battery charges almost all known mobile devices and can also be charged from any power source. The only drawback is that it requires an external battery pack.
  • Specialized energy storage device "Proglot". Universal battery. It has a variety of dedicated connectors for all kinds of devices, and its internal batteries can be easily replaced. The downside is the lack of adapters.

Universal external battery

As global all-knowing statistics show, almost every city resident has two or more mobile devices, as well as a laptop and several other gadgets. Therefore, many people strive to purchase a universal external battery for their phone, but so that it fits other devices.

This choice allows you to kill several “birds with one stone” at once: the ability to simultaneously charge all available gadgets from one device, saving money and space. At the same time, the operating rules for such devices are the same as for highly targeted batteries. In addition, modern stores can offer a huge number of batteries of different prices, characteristics and quality. Therefore, this is the most optimal choice for any user.

There is no need to buy an additional power supply for your smartphone. If you wish and have certain abilities, you can easily make a homemade external battery for your phone.

The most common homemade products are charging from batteries and from the sun. Each of them has its own characteristics. In the first case, you need a resistor, a suitable plug, 4 batteries and a special box for them. The principle of operation is simple - a resistor connects the power elements to the plug and transfers the charge to the mobile device. The downside is that the batteries need to be constantly changed.

In the case of solar charging, you can simply buy special flashlights that charge from the sun, and take the necessary elements from there. Next, a circuit is connected using a diode, and the structure is tucked into some kind of box.