2 days ago

At present, there are mainly two kinds of car jump starter power bank sources on the market, one is lead-acid battery, the other is lithium polymer.

If it is just a spare car on the car, do not have to buy batteries, buy a best car jump starter, the size and weight of the mobile phone is similar to the charge, usually can be charged when charging when the battery, when the car battery without electricity, this guy probably can start the car 4--5 times.

ECU standby power: it means that the ECU still exists power supply when the ignition switch is closed, the usual ECU has several power supplies, some are supplied by the ignition switch (+15), some are provided directly by the battery (+30), that is, the backup power supply.

Principle and function: the ECU of modern car contains a variety of functions, among which a more advanced function is "self-learning" function, which is constantly revised according to the changes of the body (environment).

For example: ignition time, throttle position, fuel injection and so on, the learning parameters are stored in the RAM inside ECU. KAM (one of RAM) is a random memory. In order to preserve these learning data, we need to provide ECU with a backup power to save data.

10 days ago

USB car charger: usually referred to as USB car charger. It takes advantage of the versatility of USB to be widely applied to various charging interfaces. Then combine the 12V DC and 24V DC to USB and the common DC 5V voltage of each charging appliance. This makes it possible to use the standard power supply on the car and the USB interface to charge the DC 5V appliances. Such as: mobile phones, MP3, navigators, game machines and all other 5V DC appliances.

Car Charger Working principle

First of all: USB car charging must comply with a principle. For the battery charging of small consumer electronic devices, the USB port is an economical and practical power source. To fully comply with the USB 2 specification, the load connected to the USB port must be capable of two-way communication with the host. The load must also meet the power management requirements, including low power mode, and facilitate the host to determine when to draw large current from the port. Although some compatible systems can adapt to most USB hosts, sometimes unexpected results occur. Only with a good understanding of USB specification requirements and load expectations can we achieve a good balance between specification compatibility and load complexity.

Therefore, USB car chargers, from interface conversion to voltage conversion, and current power requirements match the needs of electrical appliances. Sometimes you will encounter the USB you bought and cannot charge your appliance, so there may be a matching problem. For example, whether the electrical voltage you use is USB DC 5V voltage. If the voltage is correct, that is, your electrical power may be larger. USB car charging power may not match, there may be no charge, or insufficient electricity. At this point, it is necessary to confirm whether the charging current is large or small.

USB is based on the above factors: it first turns the power supply DC 12V or DC 24V into DC 5V in the car, and then transfers the output of DC 5V to the corresponding electrical appliance with the unified interface of USB. Based on the different electrical power, the power of USB car charger is different, which is different from that of USB.

USB car charger specification

USB car is filled with common specifications: output: 5V DC 500mA; 5V DC 700mA; 5V DC 1000mA; 5V DC; it can be found that the current has a variety of specifications after understanding the voltage of its specification output. The different current specifications are easy to use and choose to be applied to different electrical appliances. Such as: the previous mobile phone is basically 500mA current; but with the development of the times, mobile phone, game mobile phone, music, Internet mobile phone and so on, its power is big. So the charger needs a relatively large current. The different specifications of the dual USB car charger allow users to choose the appropriate matching specifications.

12 days ago

A lot of car owners ask questions about the use of car charger, the common problems and many people often make misunderstandings together, to tell you the correct answer, it is of great reference value!
The output current of the car charger cannot be greater than the maximum rated input power of the mobile phone.
The correct thing is that the charging current "can be big", for example, a car that output 5v/2.1 is charged to a mobile phone with a maximum rated input power of 5V/1A, which is charged to the cell phone as 1A, 2A for the tablet computer, and can be full of electricity in a shorter time; but if it is an output current of 5V /0.8A's car is charged to the same mobile phone to charge, and the input is 0.8A, not only slow in time, but also very hot. It will damage cell phone batteries for a long time. So it is necessary to choose a vehicle charger that fully outputs high quality and high current to extend the life of your beloved aircraft. General mobile phones, including iPhone, require a current of 1A (part 2A), and tablet PC is usually 2A. Then the vehicle charging with multiple USB interfaces must meet these standards.
There is no need for a car to be filled with a USB interface

Many cars have their own USB interface and may have more than one port, and most people think it's okay to use the USB interface on the car to recharge the phone or any other device. In fact, this idea is wrong, because most of the USB interfaces in the car are set for audio data transmission, so part of the vehicle's interface current is far from 5V/ 1A, which explains the reason that the charging current is "very small", if you use the USB interface on the car to the cell phone or even the tablet computer. Charging, if the current is not up to standard, the equipment will be damaged. In addition, Andrews or iPad will charge the device for charging when charging,
and the design of each vehicle is different.
The more the USB interface, the slower the charging speed is.

The current depends on the voltage, not depending on how much the USB interface is, because the current is already divided and does not interfere with each other. If it is really slower than the single USB interface, who will buy it? The manufacturer designs several U ports, mainly for the convenience of owners to charge multiple electronic products simultaneously.

But there is something on the market, the manufacturer of low current vehicles called high current output, because the greater the output of the current, the higher the demand for material and production technology, the unscrupulous merchants to save the cost really what things can be done, buy is really bad luck. But at the very least, it is good to find out early, like we do not have a professional test instrument owners, only to observe the purchase of the car charge, if at the same time to the cell phone and tablet computer, and the slow heating and very serious, is the current is not standard, it is better to quickly change to the better. The 3USB interface I use does not have these problems.
The vehicle charger must be pulled out after the vehicle is turned off, otherwise the battery will be damaged.

This statement in many places will see, in fact, most of the car is now the smoke device is already ACC and not often electricity, that is to say that the car will be able to cut off power, which is a safe practice. Even if it is to extinguish the electric vehicle, in general, the vehicle charger does not have the current output in the case of no load, so it does not pull out, and only a small LED lamp is working, the loss of the battery can be ignored. My dual usb car charger is inserted all year round, and there is no problem.
car charging must be flameout and then plug in, otherwise it will burn easily.

For many cars this is really a probability problem, which tests the shock resistance of the car, and not all cars need to be plugged out after the blowout, for example, I'm using the highest DC40V pluggable charged impact that can be plugged at will.
Do not pay attention to the maximum power of the expansion port

Many of the cars on a lot of cars have to use a cigarette lighter, so many people will buy a two or three with a smoke device extension, but the same product will often see some people say it is good and someone says the fuse is burning, which may be the maximum power of the equipment. In particular, the vehicle refrigerator, vehicle vacuum cleaner this power must first see clearly, the power is how much, see their own car filled expansion can not be used, generally in the packaging box or instructions will be marked.

17 days ago

USB 3 ports and devices have been proved to emit radio frequency (RF) noise that can interfere with the device's use of the 2.4 GHz wireless band; such devices include a wireless mouse and a keyboard for wireless communication using a radio frequency converter.

The RF noise can come from any place along the USB 3 connection. For example, if your USB 3 hard disk is inserted into the USB 3 port, the interference may come from the USB port of your hub, USB line or even drive. This noise is not always a problem, but if your wireless mouse or keyboard often disconnects, or if you have lost a click or keystroke, try to connect the mouse or keyboard to the USB 2 port and keep the RF adapter and device away from the active USB 3. 0 connection. If your computer does not have any USB 2 ports, you can use the USB 2 extension cable to move the RF converter farther from the interference source.

Devices that do not use the USB hub
Some devices must be directly inserted into the USB port of the host. When you insert them into the USB hub, they do not work at all. For example, apple SuperDrive only works when you insert it directly into the USB c hubon the apple laptop.

It is impossible to explain each installation, scene, and device, so our suggestion is to do some research before you buy: a fast Google search usually appears common problems with the device, and you will insert your center. We also recommend testing when you get a new hub, compatibility with existing USB devices so that you can return to the center if it has problems.


2 months ago

The traffic regulations in Russia are different from those in China. I think a lot of countries make way for pedestrians. As far as I can see, in addition to the lack of widespread cameras and the inability to analyze the causes of accidents, there is also the identification of responsibility between pedestrians. I have personally experienced. My friend didn’t want to go far so he cross the road, at a result, he was hit by a driver and injured. After the police saw the record, and found the it was his responsibility and he went to the police to make a record and paid a fine. Why?

The roads in Russia are very bad. On the one hand, most of the roads in big cities are not spacious, the second aspect is that Russians drive very hard, and the drunk driving rate is also very high. In Russia there is a old adage that our two great tragedies in Russia are roads and fools.

Russia's road cameras are not as good as China's, and getting evidence is very difficult. Russia's urban areas (at least in big cities) have maintained the Soviet landscape without large-scale urban construction (private property rights and cultural protection), and as a result there is no condition on the road to erect modern traffic lights and cameras. As far as I can see, I've seen similar cameras at just a few junctions.

The penetration rate is still very high, Russians usually install a car dvr camera. In the event of the accident, everything is on the video. My friends do this business, which is so good.


2 months ago

USB HUB is used for device extension connection. All USB DEVICE is connected to the USB HUB port. A USB HOST is always connected to a root HUB (USB ROOT HUB). USB HUB provides 100mA current for each port to be used by the device.

At the same time, the USB HUB can diagnose the device's pluggable operation through the electrical changes of the port and report the port state to the USB HOST by the response to the USB HOST packet. Generally speaking, the connection length between USB device and USB HUB is no more than 5m, and the cascade of USB system can't exceed 5 levels (including ROOT HUB).

The downstream interfaces of the USB Hub will divide the upstream interface bandwidth, and the USB Hub itself also needs to transmit the control signal, so the bandwidth of the downstream devices is necessarily less than the total bandwidth of the upstream device.

The actual situation is, now the mainstream USB 3 equipment is very difficult to occupy the total bandwidth (5Gbps), such as the mainstream of the 3 U disk is probably only 100MB~200MB/s transmission speed, the bandwidth is not 2Gbps, so the actual situation is not necessarily.

The principle of USB Hub is complex, and the most complex part of the USB protocol specification is the chapter of Hub. USB Hub is quite different from the Hub principle of network devices (Ethernet). If the analogy is true, the complexity is roughly equivalent to the router in the network device.

USB protocol has four modes: control transmission, Bulk transmission, interrupt transmission and synchronous transmission.

Control transmission is used to transmit instructions at the level of the control device.

Bulk transmission (Chinese name may be called batch transmission) is mainly used to transmit USB bulk data, such as U disk read and write data.

Interrupt transmission is used to transmit small pieces of data, and mouse and keyboard are mainly used for interrupt transmission.

Synchronous transmission is used to transmit data that is not strong in real-time. That is to say, it doesn't guarantee reliability. Some USB audio devices use this transmission.

USB Hub is responsible for the integration of various transmission signals of downstream devices, in which synchronous transmission is limited. If a certain proportion of the total bandwidth (memory is 20%), the synchronous transmission beyond the proportion will be discarded; the interruption transmission and control transmission occupy the bandwidth, not discarded; the Bulk transmission takes up the remaining band. Wide, if there is no synchronous transmission, then Bulk transmission can account for more than 90% of the total bandwidth.

After USB Hub integrates data, it sends to upstream equipment. If upstream has USB Hub, then the upstream device will continue to do the same operation. In addition, it needs to be explained that, in general, the USB interface on the host is itself a Root Hub, and if there are multiple interfaces on a PC, it may be that multiple interfaces share a controller, and each controller has a Root Hub.

So USB Hub is equivalent to repackaging a variety of packets, similar to a router in a network device, not as simple as a switch or a hub .

At the same time, USB Type C Hub itself is also a USB device, which is responsible for reporting to the superior of how many devices at its own lower level, and it itself also takes up some bandwidth to report its own state periodically.

Because a lot of networks such as Ethernet, such as the common network of shared HUB connections, are bus-based and are physically broadcast, that is, when a machine sends data to another machine, the shared HUB first receives and sends the data it receives to the other (the incoming port does not send) every mouth, so the shared HUB, all the network cards of the same network segment can receive data.

The internal monolithic program of the switched HUB can remember the MAC address of each port, then which machine is sent to which port to receive, instead of sending it to all the ports like shared HUB, so the network card that only receives the received data can receive the data under the exchange of HUB, of course, broadcast packets or send it to all ports. It is obvious that the working mode of sharing HUB allows two machines to transmit data in other ports, so sharing HUB determines that the same segment can only have two machines for data communication at the same time, while the exchange of HUB and two machines is not occupied by other ports, so the other ports can also be used in the same way. Shi Chuanshu.

This is the two place where the shared HUB is different from the exchange of USB HUB . Sharing HUB is the same time that only one machine sends data and all the machines can receive it, as long as it is not a broadcast data exchange HUB at the same time it can have data transmission to the machine and the data is private.

2 months ago

Samsung's flagship machine has been carrying wireless charging for a long time, and Apple iPhone 8, after changing the back of the back of the glass, finally plans to add to this convenient charging method. According to Macotakara exposure, iPhone 8 is sure to add wireless charging, but the maximum charging power is only 7.5W, and there is a gap between the latest standards for the Qi wireless charging.

Because of the Note 7 recall, Samsung's new flagship has no significant improvement in charging speed, although the wireless charging on the S8 is in accordance with the QC2.0 fast charge protocol, the power is only about 10W - considering that the wireless charging should also consider the conversion rate, the actual speed is much slower than the 15W line. IPhone8 really uses 7.5W power to charge a little slower than Samsung, but the apple cell phone has a smaller battery, and the actual charging time should not be far behind.

For Android flagship, fast charging has become one of the most basic functions. However, its impact on battery life is still to be studied. iPhone is balanced in various performance, but very conservative in battery capacity and charging speed - even if system optimization is ideal for power control, the overall endurance is still hard to meet the needs of heavy users (and iPhone8 will also carry a 5.8-inch screen). The 7.5 watts of charging power is large to ensure wireless charging and cell phone safety, and Apple should also require a third party wireless charging seat to apply for MFi certification, which means that most of the Qi wireless charging devices on the market will not be suitable for the first time and iPhone 8.

It is worth mentioning that Apple's appeal is not a Samsung power ratio, and if iPhone 8 can add wireless charging, it is believed that domestic manufacturers will also be quick to follow, and it is good for the development of wireless charging technology. However, according to the urination of apple, the wireless charging base is impossible to give to users with iPhone 8, so you want to feel the charm of wireless charging, and you have to get your wallet in place in advance...

what is qi wireless charging?

2 months ago

With the popularity of all kinds of digital devices, especially the popularity of mobile phones and tablets, the USB equipment around us is getting more and more. Every cell phone or tablet needs an adapter (charging head) to recharge, though these devices all use USB interface, but the data lines of these devices are not the same.

If you go out with friends, mobile phone running out of power can not find the adapter, it can only buy a new one, after all, many brands, the data line is the same in the end is connected with a PC, but in the end of the connecting device, usually for size considerations with different interface. Even if you look at the interface of the device now, can you really call their names? Make up for the knowledge that may be missed today. Let's know the definition and difference between common USB, micro USB and USB C together!

Three kinds of interfaces we often use

(1) Type-A: Standard USB interface

Type-A is one of our most common type of USB interface, which is commonly used on a computer. But it has some significant problems: the direction. It is necessary to insert the connector into the interface from a specific direction, but because the two sides of the USB Type c portare very close, the insertion process often goes wrong.

(2) Micro: USB standard for mobile devices

At present, most Android phones use Micro USB interface (USB Micro-B), which is still widely used in various mobile portable devices.

(3) Type-C: or will be the mainstream

Although Type-C is not long before, it can be predicted that with the maturity of USB Type-C technology, all kinds of notebook computers, tablet PCs and even smart phones will start to popularize USB Type-C port.


USB (English: Universal Serial Bus, abbreviation USB), and the Chinese referred to as " through the string line, " universal serial bus is a serial bus standard connected computer system and peripheral equipment, technical specification is an input and output interface, is widely used in personal computer and mobile devices etc. communication products, interface technology application in the field of PC.

The USB interface supports plug and play and hot plug functions of the equipment. USB was jointly proposed by many companies such as Intel, Compaq, IBM, Microsoft and other companies at the end of 1994.

The complex interface system, coupled with the need to install the driver and restart the use of the restrictions, can not avoid the trouble of users. Therefore, it is an inevitable trend to create an unitary and hot pluggable external transmission interface. It is a data transmission line that belongs to the computer connected equipment. It has a double head computer USB universal serial bus and 1 computer type 1 mobile phones.

Micro USB

Micro USB is a portable version of USB 2 standard. It is smaller than the Mini USB interface used by some mobile phones, saving space, with up to 10000 times of plug life and intensity, and blind insertion structure design.

The Micro-USB standard supports the OTG functions of USB, which in the absence of the host (such as a personal computer) under the condition that the portable device can be directly realized between data transmission, compatible with USB1.1 (low speed: 1.5Mb/s, speed: 12Mb/s) and USB 2 (speed: 480Mb/s), while providing data transmission and charging, especially suitable for high-speed (HS) or higher rate of data transmission, is connected with small devices (such as mobile phone, PDA, digital cameras, digital cameras and portable digital music player and so on) the best choice.

At the same time, it can also provide convenience for the vehicle, only need USB car charger, and then add MICRO USB data line for mobile phone emergency charging. And on top of the high grade car, the 5V output interface is directly connected to the MICRO USB line to charge the mobile phone. MICRO USB is versatile and easy to use.

Micro-USB is the next generation specification of Mini-USB. The definition of Micro series includes Micro-B series slots for standard equipment, Micro-AB slot for OTG device, Micro-A and Micro-B plug, and cable. The unique feature of the Micro series is that they contain a stainless steel shell, which is not a problem for thousands of inserting.


The Type-C interface, called USB-C, is located at the bottom of the smartphone, most of the time used for charging, data transmission, and so on. The biggest feature of Type-C double faced plug-in interface is to support USB interface double entry. It solves the worldwide problem of "USB is never inserted". At the same time, the USB data line that is used with it must be finer and more portable.

3 months ago

Now, wireless charging devices are becoming more common, including NOKIA's Lumia parts, Nexus 4, and so on. All kinds of new mobile phones that are about to be released will be expected to be equipped with qi wireless charging.

The advantage of wireless charging is obvious: getting rid of the troublesome charging line is more neatly, no power socket on the device and avoiding oxidation or ash penetration; in theory, a charging seat can support multiple devices.

In fact, there is no commonly used standard in this industry, which brings difficulties to the popularity of wireless charging. The Qi of WPC is the most influential standard at present, and it has more than 200 partners and operators.

But there are also problems with the Qi standard. At present, the technology it supports is actually called "induction charging", and the equipment needs physical contact with the charging seat. And according to the general understanding of "wireless", it should not require physical contact.

Fortunately, the latest version of the 1.2 version of Qi charging technology has increased some new functions, including the real "wireless" charging, and the mobile phone can be charged within 1.77 inches (45 mm) of the charging seat.

The new standard also allows a one - to - one charge to support up to 2000 Watts of high power equipment, such as kitchen utensils. The previous standard can only be one to one.

This new standard provides a lot of new possibilities. If the merchant can install the charging seat in the store, the user can charge the charge nearby, which has a good effect on increasing the stickiness of the user. If the car is equipped with a charging seat, you don't have to charge it in a certain place.

Competitors, Rezence and Power Matters, introduced the "resonant charging" standard before, but WPC said that Qi has more efficient power conversion. At present, the new version is still in the test, and the final conversion rate will reach 70-80%.

In fact, if according to the charging efficiency, the wireless charger is not up to the wire charging. That is to say, it will take more time to use wireless charging. However, the significance of wireless charging is that it can make full use of the scattered time. You don't have to look for a line to plug in the interface. When you don't use a cell phone, put it down to charge it, don't "charge it for a time". The use of this method is very reasonable and rational, as long as you are not on the outside.

3 months ago

Everyone hopes that they have technology products can be durable, timeless, but in the face of the habit of using the change, the reality is always cruel and skinny. Some of the things that are applied to the right place are often swept by new hardware and software, because these new rules are often more advanced, more subversive and more representative of future trends.
For example, the standard USB interface changes the common industry standard, although technology giants have been promoting the iteration of new products, but the overall replacement of the user in the hands of the stock, need to wait for a period of time, and in order to fit a common industry standard interface, users will choose to buy all kinds of transfer line silently to solve the interface the problem.

In recent years, in order to make the notebook body lighter, the manufacturers have cut off all kinds of large and functional interfaces. Instead, they are a lightweight and integrated interface system: USB Type-C. Although the market is still there are a lot of products is currently required by the adapter to access USB-C, but I believe that this transition will not last long, because some enterprises have started to develop and have released a new product with USB-C interface, in order to adapt to this new interface standard is coming, and in the layout of their products as soon as possible on the expansion of industry upgrading based on USB-C interface wave is gradually opened.

For the whole technology industry, USB-C is an accepted technology trend in the future. It uses symmetrical design without the need to distinguish positive and negative. With the latest USB 3.1 standard, USB-C has replaced HDMI, DP, VGA and USB-A with only one interface, and has high-speed data, audio / video and power transmission function. It gives the display more functionality and more interactive, which provides a new possibility for the display to become the core of the desktop data interaction. This change in the interface has triggered a data transmission revolution and an overall consumer experience upgrade.

Taking personal use as an example, I used 13 inch MacBook Air before, and in order to make my job more convenient, I equipped with mechanical keyboard, mobile hard disk, monitor and earphone. The four accessories plus laptop power basically occupy all the interfaces except SD card slot. Although the efficiency is obvious, the connection is painful.
Last month, I upgraded the office machine to a new MacBook Pro with 4 completely identical USB-C interfaces. In order to avoid a desktop mess scene, I decided to go with a USB-C interface to support the display interface compatible with the new. At present, among all the brand products sold, the selected models are not really much.