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Questions tagged [cellphone]

Questions regarding cellphones, or cellular devices. Please note that repair questions are often closed for failing to follow the Scope of the Site as described in the FAQ.

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Hooking up D-cell batteries to charge phones

I am trying to set up a disposable battery pack to recharge phones, I was able to find online a female usb cable connected to 4 AA that charges fine. when testing with 8 d-cell in series, charging 3 ...
nick's user avatar
  • 11
0 votes
1 answer
34 views

What would be the Maximum ERIP of cellphone in absence of 23dBm 3gpp restrictions? [closed]

Consider a 5g cellphone with 4×4 MIMO antaenna (4 transmitters),wifi antaenna,& Bluetooth antaenna. Considering the 3gpp guidelines, current EIRP is set to maximum of 23dBm, which is maintained by ...
Naja's user avatar
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0 votes
1 answer
94 views

Why solid state capacitors?

I've been looking through multiple cellphone chargers and I have noticed that they all use solid state capacitor for the output capacitor of the switching power supply (flyback converter). Is there ...
Mohsen Razzaghi's user avatar
1 vote
1 answer
142 views

Wireless phone charging: ways to mitigate distance (charging gap) limitations?

I'd like to use a nice, thick otterbox defender style case, and keep wireless charging, but not shell out almost $100 for the actual otterbox defender case. Those cases are sturdy and protect the ...
Jake Barbudo's user avatar
1 vote
0 answers
60 views

Real World Range of C-Band (3.7Ghz) versus EBS/BRS (2.5Ghz) mid-band 5G

I am aware that with all things being equal, lower frequencies propagate better. Thus, T-Mobile’s 2.5Ghz spectrum should have better range than AT&T’s and Verizon’s 3.7Ghz spectrum. T-Mobile ...
Jeremy Lund's user avatar
0 votes
5 answers
288 views

What type of embedded sytem is used in a mobile phone(cell phone)?

What type of embedded system is used in a mobile?Is it a microcontroller, FPGA or a DSP According to my understanding the basic and simple mobile phones like nokia 3310 used microcontroller since ...
DSP_CS's user avatar
  • 1,227
0 votes
1 answer
84 views

What indicators can I use to decide whether a power bank which I am interested in buying will appropriately regulate current and voltage?

Anker, one of the largest manufacturers of power banks, often indicates in its ads that the product in question uses a specific system, MultiProtect, to avoid stressing the phone battery which is ...
novice's user avatar
  • 101
0 votes
3 answers
172 views

Why isn't it easy to put an ampere-meter into any battery driven electronics?

I can buy a cheap multimeter which has an ampere-meter function. Great. Battery driven computer equipment like laptops and cellphones are complex, and for power / battery management I suppose an ...
Gunther Schadow's user avatar
8 votes
4 answers
4k views

Do cell-phone base station antennas emit the same power as cell phones?

Do cell-phone base station antennas emit the same power of waves as from a cell phone? I would assume so because both waves need to travel the same distance, right?
JobHunter69's user avatar
0 votes
1 answer
60 views

Is it safe to use any arbitrary charger for a smartphone? [closed]

Today, most smartphones have USB-C chargers, and this allows to use any charger with any phone. The issue I have, though, is that these chargers have different amperage, different wattage and so on. ...
Andrea Ferretti's user avatar
0 votes
1 answer
148 views

Send image using RPI to phone using Bluetooth [closed]

I'm looking to send an image file from a RPI Zero (or RPI4) to a mobile phone. The image file will be sent after pressing a push-button. The connection between the RPI and the phone is only Bluetooth (...
Gal Magen's user avatar
0 votes
4 answers
210 views

How can I use the same microphone for an amplifier and a mobile phone?

This is my first question on this forum, and I would like to say that I am learning electronics, and I am not an expert by any means. I am currently trying to realize a small project using a LM386 to ...
Miguel Hernández's user avatar
5 votes
2 answers
2k views

Why do cell phone chargers drop speed when multiple devices are connected?

What are the 'limitations' that prevent a wall charger from charging multiple devices at their maximum power? Let's say I have a 4-port cell phone charger that is rated at an unknown wattage. When I ...
deppfx's user avatar
  • 169
1 vote
1 answer
134 views

Making a "Power Wall" battery out of cell phone batteries

Cellphone batteries varies in shape and size, and most importantly, in battery chemistries. Some chemistries result in a nominal voltage under load of 3.7 V with a full charge at 4.2 V (same as 18650),...
Alwyn de Beer's user avatar
0 votes
1 answer
94 views

How to access modem inside Android mobile from a PC through USB cable? [closed]

Every mobile has a modem inside it, which allows dialing phone numbers and connecting to data/GPRS. I guess we can send AT commands to all modems in phones. So if I tear down an Android phone e.g. a ...
Nitin Sawant's user avatar
-1 votes
1 answer
209 views

How or why are powerful but low-frequency radio waves, such as from a radio station or cell tower, potentially dangerous? [closed]

Cell towers / base stations and such are limited in the power they are allowed use, even if the wavelengths of radiation used do not adversely affect people or animals. I have heard (and read) that it ...
Kurt Hikes's user avatar
2 votes
3 answers
337 views

Phone battery replacement with DC power supply

I am looking to use the Alcatel 1 cell phone without battery. For this purpose, I disassembled the battery and took out the lithium cell. Instead, I connected a DC power supply. The cell phone turns ...
Wilson Moises's user avatar
-1 votes
2 answers
74 views

Is it possible to transfer provider from one SIM card to another? [closed]

Is it possible to overwrite (migrate) provider info and details from one SIM card into another SIM card (not blank, but another working SIM card), so, when I insert that new card, the phone could ...
T.Todua's user avatar
  • 101
1 vote
0 answers
92 views

Height or antenna gain for a ship mast cell antenna

I'm optimizing my ship's WAN using cellular modems and looking to improve distance connectivity over speed in an either or option challenge. Our ship's mast has two cell antennas which are currently ...
Rich's user avatar
  • 11
3 votes
2 answers
3k views

Can you power a smartphone (no battery at all) by a power supply alone?

I have a project in mind, where I need alot of parts that quickly would make this project really expensive. Then I thought that, all the parts I need is already in a smartphone, but I don't need a ...
Repeller's user avatar
-4 votes
1 answer
727 views

Punctured and taped lithium-ion battery for phone [closed]

My phone was bulging more and more in a span of weeks. I decided to open it and remove the battery, as most likely cause. While removing it from the heavy duty adhesive, I punctured it and a little ...
Ferdinando Pucci's user avatar
0 votes
1 answer
83 views

Is it safe to charge my Android phone very often? [closed]

I still have a S9 Galaxy phone, I always try to keep the battery higher than 80%. If it goes to 80% I go and charge it up to 100% then use it (normal use) until it reaches to 80% and start over the ...
Panamanian's user avatar
1 vote
3 answers
996 views

Why can't I route USB lines through a relay?

I need to connect two phones with USB-B Micro ports through a relay. I need the relay because I need to control when the phones are connected. I made two USB-B Micro cables with wires on one end. One ...
PetSven's user avatar
  • 113
1 vote
2 answers
5k views

What does GSM 900/1800 mean?

I was looking at old Nokia 3310 phones, which have GSM 900/1800. I did some research online from a government website, along with some Google searches, to understand what GSM 900/1800 means. I got a ...
questioner's user avatar
0 votes
1 answer
181 views

What components would I need to receive SMS-CB messages? [closed]

I could simply use a LTE modem for this (with a SIM Card). But since SMS-CB is an FTA (Free-To-Air) signal, having to buy a SIM card for this (I know, it's not expensive) would be overkill. I am ...
Hugo Woesthuis's user avatar
1 vote
2 answers
125 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 ...
Devkil39's user avatar
0 votes
1 answer
61 views

how to get cell cellphone signal from far away [closed]

I am starting a ranch and would like fast internet. The ranch is 50km away. What equipment do I need to catch the cell signal from the city? What I need is internet that I try to get by cell phone.
Damian's user avatar
  • 1
6 votes
3 answers
5k views

Do phone chargers communicate with the phone?

I have come across multiple YT videos (about the new higher USB power delivery and battery degradation) mentioning that chargers communicate with the phone or laptop when charging to avoid battery ...
SoccerFan's user avatar
1 vote
2 answers
592 views

Does the Qualcomm MDM 9207 chip have WiFi, Bluetooth and GPS?

I am researching about the Qualcomm MDM9207 chip and I have some questions regarding it: Does this chip contains a WiFi module or do we have to integrate it outside? Does this chip have a Bluetooth ...
ElectronicGuy's user avatar
0 votes
3 answers
110 views

Smart phone USB-C Data and Power

I have a Samsung Note 9 with a weird technical issue that has to do with usb standards. If I plug in the phone to a PC using a USB-C to USB-C cable, the phone will charge and transfer data to the PC. ...
ryley's user avatar
  • 9
1 vote
2 answers
149 views

Mobile Signals and Amplitude Modulation

I was just introduced to the concept of Amplitude Modulation and how it was used for transmitting information between radios. What modulation technique is used for communication between mobile cell ...
bth's user avatar
  • 43
0 votes
0 answers
228 views

Tracking location with GSM tower triangulation

I want to track location with GSM tower triangulation. I searched and I found this API for GSM positioning. ...
Sun's user avatar
  • 1
1 vote
1 answer
146 views

Nearby jail's signal jammer affecting cellphone and devices using 2.4GHz band

I just rented an apartment that seemed perfect at the first sight. However, once I moved in, I noticed a lot of instability on my cellphone signal. I found that odd, so I did some research and ...
Caconde's user avatar
  • 113
0 votes
1 answer
161 views

Is there a way to determine which antenna connector is for which radio on a cellphone?

I have a cellphone mainboard from a Sony Z Ultra: There are 4 antenna connectors on the board, 3 of them unconnected (marked with red dots). One of them is connected (green wire), that might be the ...
Daniel's user avatar
  • 959
-3 votes
1 answer
701 views

Can two mobile phones accurately sense the distance between themselves?

This question is inspired from covid19 and current attempts to produce a contact tracing app for a mobile phone. Can two mobile phones accurately (+- 1 m over a range 0-100 meters) sense the distance ...
ConanTheGerbil's user avatar
-1 votes
1 answer
191 views

Will USB-PD work with and extension cable in the circuit?

I want to replace the USB type A port on my trucks dash with a USB-C panel mount and give it the ability to "fast charge" my phone. Unless there is a product that I am overlooking it seems I ...
sealfab's user avatar
  • 99
2 votes
2 answers
573 views

Why do baseband processors remain on, and communicating with the tower, when the phone is shut down?

I've believed this since 1994 - that if you really want to turn off a cell phone, you need to take the battery out. But why? What is a good technical reason to keep spending battery charge and ...
Todd Messenger's user avatar
2 votes
3 answers
2k views

Pinging a dead cellphone

Can a dead phone still be pinged? I was watching a news clip recently of someone lost in the woods with a dead phone that still managed to be pinged. How it this possible? I'd imagine it's some sort ...
tom smith's user avatar
0 votes
3 answers
202 views

How can you tell, remotely, if someone put their SIM card in a new phone? [closed]

On a recent television show, on ID Discovery, 'The Case that Haunts Me' (season 3 epi 4 'Cruel and Unusual') the lead detective finds out that the prime suspect has taken the SIM card out of his phone ...
Kurt Hikes's user avatar
1 vote
3 answers
83 views

Does data rate depends on Frequency not on BW?

If we have two RF signals of 900Mhz and 1800Mhz both of equal Bandwidth 20Mhz which one has higher data rate?
Shashank 's user avatar
0 votes
2 answers
146 views

What is meant by downstream bandwidth in lte?

In my phone, it says that the downstream bandwidth of LTE is 10Mhz. But if a carrier frequency of 900Mhz has a bandwidth of 20Mhz, i.e., frequency ranges from 900Mhz to 920Mhz, then I have almost half ...
Shashank 's user avatar
4 votes
2 answers
809 views

What kind of oscillator circuit technology is used for 5G technology?

In particular, are 5G oscillators found in cellphones using some kind of SMT/fabricated Gunn diode or Impatt diode(on a chip)? The frequency bands(K band) are beyond the range of crystal oscillators. ...
Mr X's user avatar
  • 734
7 votes
2 answers
1k views

HDMI Cable interfering with mobile phone network

Just had a "spectrum engineering officer" from OFCOM (the UK's communications regulator) visit our office investigating alleged interference from our building with a local cell phone tower. After ...
Keith Miller's user avatar
3 votes
0 answers
258 views

LTE 4G simultaneous connected devices for one cell site

I'm trying to find out how many simultaneous connected devices can handle a typical LTE 4G or 3G public cell site. I know my question sounds broad, but i'am developping an mobile application which is ...
Matthieu Charbonnier's user avatar
0 votes
2 answers
401 views

Project with smart phone like camera

I have an idea for a DIY electronics project which involves a camera where I want the camera to be small. I thought may be to get a camera component similar to the ones used in smart phones. But my ...
sergiol's user avatar
  • 391
2 votes
2 answers
657 views

How do I solder a ~20-pin USBc connector near heat-sensitive components?

I currently have an LG V20 and its charging port is deteriorating. Unfortunately, it is out of warranty and the best price that I can find to have it professionally repaired is US$60, which is about ...
john01dav's user avatar
  • 170
0 votes
0 answers
37 views

Will giving 9/12v to a quolcomm quickcharge device kill it?

Background I recently broke my phone's USB port (damn!), so as a stopgap measure before I can be bothered to buy and fit a replacement, I've soldered two wires to the +ve and -ve wires of where the ...
Jachdich's user avatar
  • 155
0 votes
2 answers
171 views

4G LTE: Is it possible to make a high gain antenna that resonates well for two frequencies, where one isn't a close harmonic of the other?

I want a high gain antenna for Verizon LTE data to my JetPack 7730L but don't really see one as high as say this MIMO parabolic antenna that's probably design for 2.4 GHz WiFi. From all I know it's ...
god_is_love's user avatar
0 votes
3 answers
691 views

Can I use a 2.4 GHz rated parabolic MIMO antenna for 700 MHz Verizon 4G LTE data?

Can I use a 2.4 GHz rated parabolic MIMO antenna for 700 MHz Verizon 4G LTE data? It seems 700 MHz are a long ways from the range of a 2.4 GHz antenna, but I have seen people marketing similar ...
god_is_love's user avatar
0 votes
0 answers
96 views

How to make a phone think it has a battery on it and run it from a charger

Im trying to run a samsung galaxy s7 edge without a battery on it but it just turn on shows a logo and then turns off again i think it knows that there is not a battery inside so if anyone knows what ...
Mega Players's user avatar

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