Questions tagged [computers]
Questions regarding architectures or design of specific parts, not consumer-related questions.
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How does a PC switch turn on a PC?
Here is my current level of understanding: virtually every PC case has a switch near the top to power on the PC. When the PC is off, pressing the switch once will power it on and the PC will begin ...
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Electrical/physical difference between Primary Memory and Secondary Memory connection to CPU
It is said that the difference between primary memory and secondary memory is that primary memory is "directly accessible by CPU", while secondary memory is "not directly accessible by ...
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USB inrush current limiting, charging super capacitor
I am trying to charge a supercap over USB. I understand I need to limit the current (ref: usb.org)
This has been discussed a lot here, for example: here and here, but I believe my requirements are a ...
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How damaging are inrush currents?
Typical power supplies will have 30 to 100 amps inrush current at 220v, sometimes less, sometimes over that. How is it that the power strip rated at max 10amps at 220v doesn't get damaged?
Also, if I ...
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Ben Eater's 8-bit CPU: I can't get the register to load data on the bus
I am following Ben Eater's 8-bit computer series. I am currently working on the register. The clock is working fine. However, there are two issues:
When the data loads on the bus (for more detail, ...
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Problem with the smallest negative number using Signed-2's-Complement
I have a problem figuring out why the smallest negative number we can represent in 3 bits, using Signed-2's-Complement is -4.
I understand that in S2C format, we can create numbers from 2x-1-1 (...
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Is the purple wire on an ATX power supply always +5V stand by?
I'm trying to use an old 20 pin ATX power supply as a substitute for the failed power supply in a Dell Optiplex 7040† I managed to find the pinouts for the Dell power supply which only has two output ...
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Voltage-drop resistor to power a 19 V computer
I am considering using a voltage-drop resistor to drop the 21.6 V ± 1% on a power supply down to 19 V.
If this was an LED, I would use a 1 Ω, 7 W resistor but this seems to be a very big size.
In this ...
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Is there a practical reason for making laptop AC adapter bricks at the plug end?
All laptops require a AC adapter in order to convert electricity into a usable form for the laptop. In most AC adapters I've seen, the plug is directly connected to the power brick, meaning that the ...
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Reset mainboard from Raspberry Pi
I have a desktop computer with an Asus mainboard TUF_GAMING_B550-PLUS and a Raspberry Pi 4.
I log in remotely to the computer, but unfortunately from time to time it has an operating system issue, ...
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How many transistors at minimum do you need to build a general-purpose computer?
I'm wondering what the simplest design for a general-purpose (Turing complete) computer is. To my surprise, I haven't found much on the web. Surely this is a known problem?
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How to connect an activity LED to a RocketRAID card? [closed]
So this is more computer-based, but definitely electrical so I'm hoping I can find some help, so here goes...
I have a home server (WSE2016) which utilizes a RAID for its primary storage. I had an ...
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Driving a DVI monitor from a monochrome source
I have a plasma display EL8358MS that is defective (burnt out.) The display has a signal convertor with these inputs:
...
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Why do inductors in motherboard VRMs have high-voltage build-up without diodes?
I just watched Bullzoid/Actually Hardcore Overclocking's video on how VRMs actually work, and I have a question.
First, in my understanding, the diodes in the VRMs are included to stop the inductor ...
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How are the transistors in motherboard controlled and timed?
I just watched Bullzoid/Actually Hardcore Overclocking's video on how VRMs actually work, and I have a couple questions.
In the video, the Bullzoid mentions how the transistors are switched on and off....
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Confusion regarding future scope of electrical & electronics engineering jobs (generally world wide and especially in India) [closed]
This question is seeking advice generally for world wide and especially for Indian region(India and its neighbour countries having almost same economic conditions like India)
If anyone has no idea ...
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Why do SSDs have a limited lifespan?
Why do solid-state drives even have a limited number of read/write cycles, usually 100,000-300,000 cycles?
For hard-disk drives, it is understandable why they wear out. That is because they have ...
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Way to measure delay propagation between two different systems
I have a system that sends data from one location to another via radio and I needed to find out the point to point delay propagation from the sensor measurement on one side to the reception on the ...
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How did the vacuum tube computer technicians know when a tube had failed?
I have read that in vacuum tube computers, a tube would fail every couple of days. How did the technicians know that a tube had failed?
Wouldn't a broken tube silently cause the calculations to ...
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Are there risks to running one computer with two completely different power sources? [closed]
I have experienced two computer power supplies using the same main power utility company here (same breaker, just different circuit). I am planning out an off-grid system, am considering running one ...
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How does the switch on the back of older computer power supplies work to vary between 110 and 220 volt input?
There is a little switch on the back of older computer power supplies to select between 110 and 220 volt AC input. I imagine this switch enables/disables a 220 to 110 volt transformer. Or perhaps a ...
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Why does a flip-flop's outputs have to be the inverse of each other and an invalid/forbidden state discouraged [duplicate]
After reading, researching, and asking questions about flip-flops.
My understanding is as follows:
They are not the only means of storing state but are one of them.
The circuit has been constructed ...
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Why are flip-flops criss-crossed?
I want to simulate how a computer works using logic gates. Right now I am trying to build the memory aspect of it.
After looking at various articles and books I see a lot of them using flip-flops/...
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HDMI: Can a computer still detect a monitor properly if some of the TDMS pins/wires are damaged? [closed]
Can a faulty HDMI-cable with damaged TDMS pins/wires still work to the extent that the computer can still detect the monitor, but the monitor just will not display anything (except for no signal)?
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A component has blown on my HP elite book 840 G6. I need help identifying it if it all possible
Here are the pictures. It was late and I shorted 2 pins of the smart card reader ribbon connector. Don't know how such a stupid mistake, but this component on the other side of the board went up and ...
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I’m getting little more than 12 V in my computer PSU, should I use it?
I bought a refurbished computer ATX PSU, it had the most generic PCB I have ever witnessed. Seems like has a optocoupler and works with sdc2921 IC.
In 12 V rail I’m getting 12.25 V.
In 5 V I’m getting ...
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ESD Wrist Strap When Working on Monitors and Power Supply
My book for the A+ exam specifically says not to use ESD for repairing monitors or power supplies.
Why is this? I understand that their capacitors hold lethal amounts of charges, but the motherboard ...
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Looking for an explanation of grounding in relation to computers and DVI-HDMI adapters
I recently found that a DVI-HDMI adapter, purchased to connect the micro-HDMI port on my new Raspberry Pi 400 to the DVI port on my monitor, behaves strangely: it works well when connecting to my ATX ...
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My Professor and I are debating about absorption law
So the question is \$(w+y)(wz+wz')wy+y\$ and this is my answer by absorption law where \$A+AB=A\$:
$$
(w+y)(wz+wz!)w y + y\\
B A + A
$$
So the answer is \$A=y\$.
My professor said I ...
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Old computer socket disconnection, cleaning, and repair [closed]
I have very old computers; from time to time the RAM disconnects. I remove the DIMMs, clean the sockets using Isopropyl alcohol many times until it works again.
It will be fine for few weeks, but I ...
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Calculating the required voltage supply [closed]
There is a Single Board computer that gives a range of input supply as xvolts - yvolts.
Let's say we add a few more additional components like webcam or additional storage drive.
Taking these into ...
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Electrical reason for the minimum altitude (-50 feet) in the computer specs?
Are if there any electrical reasons not to operate or store my Dell OptiPlex computers below the altitude of -50 feet, as written in the specifications?
Screenshot of the original Dell OptiPlex ...
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Enable vendor-disabled hardware on tablet? [closed]
I have a nextbook tablet (one of those cheap things from walmart) that I was looking to try to improve the RAM situation on to breath some new life into it as it apparently only has 1G of it. I ...
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Backwards compatibility of PCIe AC coupling capacitors
The PCIe base spec mentions that platforms operating only at 2.5GT/s or 5GT/s may use AC coupling capacitors in the 75nF-265nF and that platforms supporting 8GT/s and above must use 176nF-265nF.
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Why aren't current CPUs designed for more powerful cooling systems? [closed]
Chips on the present can't get smaller, higher speeds and voltages increase heating, so why don't CPU manufacturers aim for more powerful cooling systems instead of looking for parallelization?
We are ...
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What is the most important CPU price factor [closed]
I have two intel CPUS with distinct features.
intel i7 8550U
intel i5 8300H
Which have big performance difference with the cheaper 8300H being higher in memory ...
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Where or when is it unsafe to clean using compressed air? [duplicate]
There's this lesson on ICT for us in cleaning computers and their equipment. One of the components that can be used for cleaning is something called compressed air.
Just to make sure, which computer ...
user285263
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Was the Intel 186 chip commonly used anywhere? Was it only found in industrial computers? Why not PCs?
I don't think the Intel 186 was in any "home computers" or PCs, but I see other people referencing it as a common chip. Also, I've heard that NEC V20s had the 186 instruction set in addition ...
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Will a computer fail sooner the more you use it? [closed]
Is a computer like a car in the sense that the more you use it the quicker it will break down? Assuming that we have a regular computer with SSD that is running 24/7 versus a computer that is run ...
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Why can't you make a thunderbolt 3 hub?
So laptops with thunderbolt 3 are pretty common, docks are common, every other kind of USB seems to be able to be used with a hub. I know thunderbolt 3 can be daisy chained, theoretically eliminating ...
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Which alcohol is bad to use when cleaning computers?
I heard there are some alcohols that are prohibited to be used when cleaning a computer or an electric device.
Apart from beverages, which ones are these?
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Doubt in pipelining forwarding in MIPS
I am fairly new to computer architecture and having a tough time solving problems based on pipelining. I was trying to solve a problem from this pdf I found on Google
I have a doubt in part ...
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reversal of computer camera image [closed]
Why do so many embedded cameras in computers, etc., prsent a mirror image? It means anything with writing on it is backwards.
Why is this desirable?
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How do I send a signal from my computer to my USB antenna
I'm trying to make an RC car that can be controlled by my computer.
The heart of the car is a simple mother board from an old toy. It basically accepts a signal 49MHz from a controller with a 9V ...
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PWR ON motherboard with Touch sensor TTP223 and Transistor
I have a TTP223 touch sensor, a BC347 Npn transistor and 10Kohm resistor. I want to make a touch button as substitution for my pwr physical button on the case of my pc.
On the motherboard I have 2 pin,...
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Why do server mainboards use different capacitors for their VRMs?
Recently I noticed that server mainboards use a different type of capacitor as part of their VRMs (after the inductor). I believe they are ceramic capacitors, whereas consumer boards usually use ...
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PC ATX12VO (12V only) standard - Why does everybody say it has higher efficiency?
To my understandings, the new 12-volt only standard moves the 5V and 3.3V supplies off from the ATX power supply "box" to the motherboard.
According to PC World (which is cited by Wikipedia),...
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What type of electronics is typically used to interface between PCs and custom hardware? [closed]
I have tried to make this question acceptable for StackExchange, I am not looking for buying advice, just either examples of hardware that could have been used or the name of types of devices I should ...
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using citric acid alcohol solution to clean rusted terminals
I used to clean old computer sockets and terminals with citric acid solution in alcohol. It worked fine for long time, but for the tiny connectors of DIMM Ram sockets it works for a very short time ...
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Has there been any deliberate implementation of combinational logic soft error correction in any consumer-level product, like a CPU/microcontroller? [closed]
Prologue
It is well known that many error detection, mitigation, and correction methods, such as parity or ECC, have been available in large memory banks, like for RAM, for decades now, and even in ...
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