Questions tagged [mobile]

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Assisted GPS (AGPS) on SIM7600 module does not work

I recently got a SIM7600G breakout board and wanted to use it with the CGPS functionality for A-GPS. It works with connecting with my SIM to the Internet and all, but when I try to use AT+CGPS=1,3 (UE-...
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0 votes
2 answers
107 views

How Mobile Phone Call Works [closed]

This may be a noob question, but I'm having a hard time and confusion finding the answer. How does a mobile phone call work in the mobile phone itself so that analog data (voice) is transmitted out of ...
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1 vote
1 answer
97 views

What is the maximum transmission power of a 4G/5G phone with multiple antennas?

As we know, a user equipment (UE) can transmit its traffic with the power up to 23dbm. However, there is few materials mentions the maximum power a UE can apply if it has multiple antennas. In this ...
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0 votes
0 answers
104 views

SMD Component blown in earphone circuit in S9 mobile phone - please help identify and how?

Hi all, I am trying to identify the components marked "MT" and "7" in the first picture. They are in the earphone circuit of a UK Samsung S9 G960F mobile phone. The repair company ...
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2 votes
1 answer
96 views

Is it safe to use my phone while charging it? Does a charger leak electricity? [closed]

My cousins always tell me that it is not safe to use or call someone on a mobile phone while charging it. Is this just a myth or is this true? I read somewhere that most phone chargers are isolated(...
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1 vote
1 answer
107 views

Are there fewer firmware chips in a mobile device compared with a laptop or a desktop?

For a conventional laptop or desktop computer, there appear to be many firmware chips in which malware might hide: internal drives network card graphics card sound card embedded controller BIOS ...
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0 votes
2 answers
184 views

3G, 4G, 5G and 6G simple differences [closed]

Seems like a simple question but I've searched and not found good answers. It comes down to signal to noise ratio equation. What are the differences between the generations in terms of: Frequencies ...
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2 votes
1 answer
176 views

Why LM2596 buck converter output current is low when used as a mobile charger? [closed]

I am having LM2596 buck converter which is capable of providing 3A current and my input source is capable of providing 5A which is a transformer. but when i used the buck converter to charge my ...
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  • 131
1 vote
0 answers
75 views

can someone help me build a usb jig to force android device into recovery

Years ago i bricked a phone trying to install a ROM not designed for that phone. As a result the phone went into a bootloop and would not go into recovery mode. Researching the problem i found a ...
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14 votes
9 answers
6k views

Why doesn't higher frequency mean higher data rate?

My question is very primitive :) I've read multiple articles today and answers here, on Stack Exchange, but still don't understand one thing. Why doesn't frequency itself affect data rate in mobile ...
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  • 157
1 vote
0 answers
68 views

What are these mobile pixels?

I've got this picture under my microscope for an old Samsung Galaxy Ace mobile phone, I'd like to know what are the different pixels in the rows with a separation in the subpixels? And how are they ...
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0 votes
1 answer
35 views

USB manipulation using mobile phone

I wanted to design a clock based system that would do a task at a certain time, but I do not possess a microcontroller like Arduino due to lockdown(Corona pandemic). My task involves making a motor ...
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0 votes
0 answers
47 views

Phone replacement parts: original vs copy

I'm looking to buy a replacement micro USB board for my Xiaomi Redmi 6. As your can note for example on this product page, there exist "original" and "copy" versions for the same component. The "copy"...
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3 votes
1 answer
61 views

Details about Total Access Communication System (TACS)

I'm not sure if this is the right place to ask. I am trying to build a base station for a TACS (Total Access Communication System) phone, but I have not found any detailed document about it. The most ...
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1 vote
1 answer
422 views

Can mobile reception 4G/5G signal reception be affected by atmospheric changes?

For example, if it rains or there is smog in the air can this atmospheric change affect the signal quality of mobile phone devices such as 4G and 5G? I have been noticing changes in the reception ...
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  • 189
0 votes
1 answer
66 views

CDMA basic working principle

I find it hard to find on the internet a simplified explanation of the principle of operation of the CDMA system. Could you give me an example of how it works and how a receiver can correctly identify ...
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0 votes
2 answers
139 views

Battery life impact with fast charging

Typically fast charging reduces backup time and life. Now a days almost all handsets are coming up with different fast charging capabilities. I'm currently using Galaxy Note9 which has fast charging ...
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-1 votes
2 answers
90 views

Is there so much of a 'technological quantum leap' in 5G technology? [closed]

AFAIK, it is only the antenna hardware that goes into the smartphone/tablet and also the base-stations, where the technological breakthroughs can realistically be present. Every other component of the ...
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2 votes
4 answers
602 views

Does a poor mobile network signal cause faster battery drain? [closed]

Quite a simple question actually, does a poor mobile network signal cause faster battery drain? If so, is there a difference between 2g/3g/4g/5g in the speed at which the battery drains.
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0 answers
59 views

Default behavior of a USB device in the presence of 5v [duplicate]

This is a follow on from this question Given a home made USB charger that simply provides 5 volts across the GND and VCC pins of a USB port, what should the default behavior be of any mobile device (...
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4 votes
3 answers
369 views

Why can't the orthogonal PN codes help in the near-far effect?

The CDMA near far problem arises because handsets may be anywhere within the particular cell boundaries. Some handsets will be close to the base station, whereas others will be much further away. In a ...
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2 votes
2 answers
214 views

Feasibility of custom parabolic mic (amplified, bandpass filtered) for use with mobile phone app [closed]

I am not an electrical engineer, but I am up for a challenge and this is my first venture into electrical engineering. However I am beginning to think this may be a step to far! As a hobby I survey ...
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0 votes
1 answer
65 views

What is sitting inside LED array so that I can create my own drivers?

I have a LED array and an app to drive it: https://itunes.apple.com/US/app/id1431362600?mt=8 https://play.google.com/store/apps/details?id=com.yskj.led&hl=en_US I connect to WiFi and I'm able to ...
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0 votes
1 answer
44 views

Reconfigurable antennas at base-station

Can reconfigurable antennas be used at base-stations and cellphone towers? I read that MIMO antennas are used at base-stations for 4G systems (and will be used for 5G). Are these antennas ...
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0 votes
3 answers
830 views

AC voltage on the outside surface of micro USB charger cable

My micro USB mobile charge cable is having about 98V AC voltage on the outside surface. (PFA measurement image. The black probe is connected to the Power socket Ground port. I could not take the whole ...
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2 votes
1 answer
2k views

Analog beamforming vs digital beamforming

I am reading some research articles on wireless communication where they talk about beamforming techniques and their differences in Multiple antenna Tx-Rx systems (MIMO). It says analog beamforming ...
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  • 155
0 votes
2 answers
116 views

Batteries have a constant charging speed from 0%→70% instead of being any faster at 0%?

A mobile phone I tested keeps charging at the same constant speed from 0% to 70%, which is 10 watts. It uses MediaTek PumpExpress (input power: 12V 0.83A, despite the wall charger is capable of 12V 1....
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-2 votes
1 answer
183 views

How is 4g much faster than 3g? [closed]

The data rate for 3g is up to 2Mbps but for 4g it's up to 20 Mbps or more. But the frequency Band of 3g is 1.8 - 2.5 GHz but for 4g it's 2 - 8 GHz. I understand that increasing the frequency band ...
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-4 votes
1 answer
135 views

Hack smartphone IC to draw more current and allow higher voltages? [closed]

Disclaimer: This is just a laboratory experiment I am willing to do at my own risk. I understand the risk of blowing up the phone (GT-S5280) pr charger (Powstro 30W charger). I already have a water ...
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1 vote
1 answer
2k views

USB-C UFP and DFP Not Working Properly with ONLY Samsung Mobile Phones

I have a UFP device (basically just a light) that I am trying to sink for power only. The "light" has a micro-B plug, which then plugs into a micro-B port on a PCB, that then includes a USB-C plug ...
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0 votes
2 answers
246 views

Does a mobile phone app have the ability to control the output current?

After some brief research online, I found that the USB port is capable of starting a simple fan. Meaning the USB charging port can output current into an external device. Which leads to my question, ...
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0 votes
2 answers
26 views

Manually control smartphone power current drawing during charge?

How can I manually control, how much power the smartphone does draw? Sometimes, a smartphone does accidentally consider a charger as much weaker than it actually is. Sometimes, a boost converter/...
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0 votes
1 answer
140 views

What happens if more voltage hits your mobile phone charger? [closed]

I am new here an i want to know that in the country i love AC voltage is 240 volts but sometimes it exceeds the limit. what happens if voltage like above 300 volts hits your mobile phone charger what ...
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1 vote
2 answers
1k views

Power old Nokia phone from Bench Power Supply

I have an old Nokia Mobile that has a dead battery. I am trying to power it up to see if it works without having to purchase a replacement battery. I have a bench power supply but am confused as to ...
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-3 votes
1 answer
89 views

Is it possible to move an internal SD card from a Samsung Galaxy S3 into another phone (Galaxy S2) to retrieve the information from the card? [closed]

Is it possible to move an internal SD card from a Samsung Galaxy S3 into another phone (Galaxy S2) to retrieve the information from the card, or is there any other way to access the information from ...
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0 votes
3 answers
2k views

Can SMPS works as cellphone charger?

I tested for charging a mobile using SMPS, it charges the battery 10% percent in an hour. But when I connect the same mobile to the mobile charger it charges the battery 40% in an hour. The SMPS ...
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0 votes
2 answers
59 views

Connecting mobile battery and LED bulbs to 10.5v Solar cell

I want to connect a 10.5v solar cell to a number (say 10 to 20) of 3v LEDs with an ordinary mobile battery for power backup (charging the battery). Should I use a resistor? What else I can do in an ...
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-1 votes
1 answer
48 views

(W)CDMA, any repeating information?

I am looking to characterize a WCDMA channel to study the effects of multi-path. In order to do this I need to be able to find some repeating information (bit sequence) being transmitted by a station. ...
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0 votes
2 answers
281 views

voltage output on double USB chargers

I'm a beginner: If the mobile phone charger has two USB ports for output and the charger is labeled 4.8A, does it provide 4.8 maximum to both ports or to each port when cables and mobile phones are ...
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1 vote
1 answer
83 views

Why do faulty headphones make MP3s sound low bitrate when I touch the wire? [closed]

I have a pair of headphones which came with my phone. They're the standard type that comes with a mobile phone - TRSS 3.5mm jack with an inline microphone. I was listening to Spotify on my phone. I ...
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  • 654
0 votes
2 answers
87 views

I need an aerial adaptor for my 4G modem. What are the names of these types of coax connectors?

I have a 'Mifi'™ 4G modem. I ordered an external aerial for it, but the diameter of the connector is about four times the size I need. I want to buy an adaptor, but I don't know what search terms to ...
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0 votes
1 answer
106 views

Mobile Power Bank 18650 Battery Charger [closed]

My question is about the below power bank charging module. We connect 3.7V 18650 type batteries to this module. Then the output voltage of this module via USB is 5V. My question is how it returns 5V ...
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0 votes
1 answer
78 views

Will this N-Channel Mosfet work as high-current motor controller?

We are building a mobile robot which will use two motors in a differential drive configuration to maneuver and move around, and we want to choose the right driver IC or transistor circuit for the job ...
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2 votes
2 answers
364 views

Powering multiple cellphones with a DC power supply

I have about 100 cheap cell phones that need to be on 24 hours a day. Unfortunately (likely due to the cheap nature of these phones) the batteries end up bloating after a couple months of being ...
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-6 votes
1 answer
90 views

How does signal 4G dial as a Wi-Fi signal through tethering? [closed]

I am looking for the datasheet (internal circuits of embedded mobile) of 4G modules, and I would like to understand how this module, electronically, is connected to the wi-fi module in the same phone. ...
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0 votes
2 answers
190 views

Anyone an expert on mobile LCD displays? [closed]

Reason I ask is, I've noticed with water damaged iPhone 6 screens if the pins on the connectors of the screen itself have corroded and you fix them with cleaning and fresh solder or jumper wires 8 out ...
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2 votes
4 answers
5k views

How to power a phone with no battery properly?

I have an LG G3 phone that I want to use as a stationary device and leave it hooked up permanently. I prefer not to do it with a battery for various understandable reasons. My questions are: What ...
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1 vote
1 answer
145 views

Does 2g/3g rf receive circuit path work for 4g if they are in the same band?

I am wondering that if the rf receive path for gsm/wcdma can be used to receive lte fdd signals? provided that gsm/wcdma/lte are in the same band e.g. band8 downlink frequency 925-960mhz, and the ...
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1 vote
1 answer
122 views

Making a mobile battery charger for smart phones [duplicate]

i want to make a mobile charger and charge multiple mobiles at a time therefore i select a 5V 2A adapter and a USB hub with 4 ports check the image what i am going to do with this adapter and USB ...
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1 vote
2 answers
922 views

Why do mobiles phones have non removable batteries at all? [closed]

Doesn't a removable battery have a lot of advantages over a non removable battery? In case the phone drops in water/the battery gets faulty due to whatever reason, we can always change the removable ...
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