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Questions tagged [mobile]

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4
votes
3answers
257 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 ...
2
votes
2answers
82 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 ...
0
votes
1answer
42 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 ...
0
votes
1answer
34 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 ...
0
votes
2answers
87 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 ...
1
vote
1answer
431 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 ...
0
votes
2answers
92 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....
-2
votes
1answer
136 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 ...
-4
votes
1answer
78 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 ...
0
votes
1answer
347 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 ...
0
votes
2answers
48 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 to start a simple fan. Meaning the USB charging port can output current into an external device. Which leads to my question, is ...
0
votes
2answers
25 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/...
0
votes
1answer
78 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 ...
1
vote
1answer
120 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 ...
-3
votes
1answer
69 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 ...
0
votes
3answers
906 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 ...
0
votes
2answers
39 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 ...
-1
votes
1answer
42 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. ...
0
votes
2answers
80 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 ...
1
vote
1answer
79 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 ...
0
votes
2answers
73 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 ...
0
votes
1answer
84 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 ...
0
votes
1answer
64 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 ...
0
votes
1answer
177 views

Phone battery modification, transplanting a PCB flex onto differing voltage?

I'm contemplating getting a Sony battery's PCB flex soldered to a Samsung S8+ battery. This due to new official genuine products proving impossible to find for a 2014 device now, especially with a ...
1
vote
2answers
83 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 ...
-6
votes
1answer
74 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. ...
0
votes
2answers
151 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 ...
0
votes
3answers
1k 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 ...
1
vote
1answer
137 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 ...
1
vote
1answer
95 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 ...
1
vote
2answers
471 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 ...
0
votes
0answers
48 views

What is the SAR(Specific Absorption Rate) value near a Telecom Tower?

We know the SAR values of every smartphone. However we've got so many cellular towers in our neighborhood. How much of risk is there, health-wise, in being exposed to them daily? I mean is there any ...
-1
votes
4answers
535 views

practically how to estimate the exact distance between transmitter and receiver in wireless network [closed]

I want to know the estimation of exact distance between transmitter and receiver in wireless networks. Can the distance be calculated? What would I have to do to find the exact distance?
0
votes
2answers
84 views

Can you get electricity from your mobile phone [closed]

Does someone know if its possible to get energy from your phone (android/ios)? I want to charge a capacitor or a very little Battery and thought about the idea to get this energy from your mobile ...
-1
votes
1answer
91 views

Mobile device 2.6V power source required [closed]

The title says it all. I need a 2.6V voltage source for a selfmade mobile device. I would appreciate any help on wich batteries (rechargable or not) to use for that. Thanks! Further information, as ...
2
votes
1answer
3k views

Wiring power banks in series for 25V output to power e-bike

So I have an old electric bike sitting around, no battery. Replacement 24V 10Ah batteries are $200+. However, I have/can get 10Ah power banks (to charge phones) for under $10. They all have standard ...
0
votes
1answer
51 views

About charging Li-ion batteries in mobile devices [closed]

I've got some questions about charging Li-ion batteries in mobile devices. Does mobile phones that are made by major manufacturers like Samsung have solutions for charging safety in their devices? If ...
0
votes
4answers
189 views

Why is a cellphone charger rated like that?

Here is what I read on the nameplate of my phone charger: Output 5V DC 1A. So, I think the Max. Output power is 5 watts. Input: 100-240 AC 50/60Hz 200mA. I assume that the mains voltage is 100 ...
-1
votes
2answers
159 views

Which chip remains on when the phone is switched off but it has to detect if the power button is pressed to switch it on?

I wanted to know which is the chip that runs to detect when the power button is pressed to switch on the phone. Is the real time clock and circuit and this chip connected in any way?
0
votes
1answer
643 views

External power supply a mobile phone

I have an alarm device. It convert 12v to 4,3V to the phone. It's outputs are 4.7V, GND, and two output to the phone buttons If the inputs loop of the alarm device is opened that means the wire have ...
3
votes
2answers
1k views

cell phone detector circuit

i have successfully implimented below circuit for active cell phone detection but i dont seem to understand the working of this circuit,if someone could explain it would be a great help.Thank you.
-3
votes
3answers
384 views

Commnication between mobiles which are in range of 100 meters without using any mobile tower for free [duplicate]

Every mobile radiates its signal to its nearest tower during phone call.Then is it possible for two mobiles to communicate with out using any tower with in range of 100 meters or more .If it is ...
4
votes
1answer
449 views

Getting started with Qualcomm reference designs

I am looking to get started with Qualcomm Reference Designs. I am partly inspired by this article: "Start Your Own Smartphone Company for $1,000". I have an application that I would like to be able ...
2
votes
1answer
357 views

Wifi uplink air interface

Most Wifi 802.11 standards use OFDM to achieve high data rates wirelessly. However, I was told OFDM is not suitable for uplink as it requires expensive and inefficient amplifiers which are not ...
0
votes
2answers
759 views

mobile phone direct power

I've got a few HTC Desire A8183's in which I would like to power directly off the wall socket. I've got a 12volt 1amp transformer which I've put through a voltage regulator to bring that down to the ...
0
votes
2answers
376 views

Bike mobile charger

Hi, I've made a battery operated mobile charger using this circuit. I am able to charge the basic phones (with 2100mAh battery) with it. But the problem is, I couldn't charge any smart phones (with ...
-1
votes
2answers
11k views

Effect of WiFi hotspot usage on mobile phone circuitry [closed]

Despite the fact that mobile phones come in wide a variaary and form different suppliers and with different software, most mobiles todays have a WiFi hotspot feature that can convert a mobiles' ...
3
votes
4answers
4k views

How does the mobile 3.5mm audio port work, and Can I light a LED from it?

I am trying to do this, light a LED from the headphone wire(mobile) but it seems it gives ac in there, I don't have much idea, please help.
1
vote
0answers
479 views

What is Virtual Array Antenna?

What is virtual array antenna (VAA)? I have searched it everywhere but i was unable to find direct answer to this question. I know this concept was built from phased array antenna. Please explain ...
0
votes
1answer
800 views

How is the output voltage of a mobile phone charger fixed to a rated value? [duplicate]

Here is the circuit of cellphone charger. I have seen the input voltage range for a cellphone charger to be 100-230 V but the output voltage to be fixed to the rated value(like ~4.5 V). So, my ...