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.
279 questions
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Communicating 1/4 miles without Wi-Fi. (I want to design a driveway alarm.) [closed]
We live in a very rural area of Ohio. Our driveway is 0.25 miles (400 m) long. I would like to design an alarm that will alert us when someone turns into our driveway.
The easy part is the optical ...
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How can I record with this old fashioned mono microphone? [closed]
I have this microphone that comes with a 3.5mm mono jack connector.
When I plug it in to my laptop or my phone it won't work, and I believe the "mono" part is the problem. What do I need to ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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?
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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. ...
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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 (...
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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 ...
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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 ...
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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),...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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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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.
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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 ...
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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 ...
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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. ...
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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 ...
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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.
...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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?
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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 ...
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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. ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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