Questions regarding architectures or design of specific parts, not consumer-related questions.
3
votes
3answers
82 views
Use a power supply as a switch
I have some extra fans to cool my Xbox (4). I think that they would drain too much power if I connected them strait to the internal Xbox fan. So I want to know if I have a power suppliy for the extra ...
1
vote
0answers
68 views
computer build problem — no video output [closed]
I am having a problem with one of my first computer builds. It is all old parts; I am building outside the case to test the main components: the cpu (w/ heatsink & fan), the memory, the graphics ...
-1
votes
1answer
90 views
Good battery back for home computer (e.g. iMac, PC) in case of power cut [closed]
I am wondering it there is anything in commerce such as a battery pack for home computer (e.g. iMac, PC) to connect between the computer and the electricity cut and safeguard the computer from any ...
0
votes
2answers
162 views
A Strange Computer : Cache based computer [closed]
In the Operating System class I heard from Professor that in some institute, researchers are working on cache based computer ( means the computer that don't have RAM and have a big cache ( probably 1 ...
3
votes
3answers
254 views
Memory (RAM) of computers after shut down
After computer shuts down, is it possible to retrieve data in RAM? I heard that police was able to do that... so I felt that was somehow weird..
0
votes
1answer
806 views
Is there a formula describing the relationship between bit error rate, frame size, and normalised effective throughput?
Is there a formula describing the relationship between bit error rate, frame size, and normalised effective throughput?
to clarify, normalised effective throughput is the same as channel utilisation.
...
2
votes
1answer
165 views
Resources for IBM PC compatible motherboard / Intel 80486 development
I'm trying to find some resources on designing motherboards, but there doesn't seem to be much out there. I'm also looking for information about interfacing with an Intel 80486. I mostly understand ...
0
votes
1answer
94 views
Electric flow rate (Amper) on the com-port
I have sending data through com-port from PC.
Is there a constant rate of flow of electric charge (Ampere) when the com-port is used while sending or not sending data through it? Does the Ampere on ...
-3
votes
2answers
97 views
Computer power source [closed]
I have a computer that stopped working and I think the problem is the power source but I'm not sure.
I have other power source from another computer that I would like to use to test but first I would ...
1
vote
1answer
256 views
IEC 60320 power cord rating
I am trying to determine what power cords I need to get to connect computer servers to 208v PDUs.
I know the PDU has C13 receptacles I need a C14 to C13 power cord. However, I noticed there are ...
4
votes
3answers
470 views
Why do the large transistors on computer components have their middle pin cut?
I have seen transistors with the middle pin cut used in computer equipment. What do they do?
1
vote
2answers
110 views
Looking for a USB/PCI controller that can replace a physical switch
I am looking for a component that I can drop into a circuit that will replace the functionality of a physical switch so that I can control it via computer, preferably via a standard interface (USB or ...
3
votes
2answers
566 views
Designing a single-board computer and getting it manufactured
I would like to design something like the Raspberry Pi and chromebox and get a few manufactured as a hobby learning experience.
I come from a background in theoretical computer science and ...
1
vote
2answers
401 views
How can I separate the sync signal from a composite video signal?
I have a small device (based on an AVR microprocessor) that outputs a Black & White composite PAL video signal, designed to be plugged into a TV. I also have an old Amstrad CTM644 monitor and want ...
0
votes
1answer
260 views
Can I control a model train with a lighting dimmer pack?
I have an O-scale 3-rail track model train. I would like to be able to control this with a computer.
The normal model train transformer/controller goes from 0VAC at "stop" to 18VAC at "full speed".
...
3
votes
3answers
1k views
Why does a speed-controlled computer fan require 4 pins?
A "standard" computer fan has two pins; one for power, one for ground. A three-pin fan adds an additional pin used for the signal from the hall-effect sensor. A speed-controlled fan generally uses a ...
1
vote
1answer
63 views
what do i interpret from these memory labels?
What do i interpret when i see this configuration for some cache memory : 512 x 12 or for a main memory with a label 32k x 12 ?
...
1
vote
3answers
442 views
Get 12 volt power supply from Dell Laptop
Is there any way to get a 12V supply out of my dell inspiron 9400 laptop?
I have an external 2.4Ghz video receiver which I want to power from my laptop without using a separate battery.
Could I just ...
2
votes
2answers
583 views
Is booth multiplication algorithm for multiplying 2 positive numbers?
Is the Booth algorithm for multiplication only for multiplying two negative numbers such as \$-3 * -4\$ or can it also multiply one positive and one negative number such as \$-3 * 4\$? I believe that ...
5
votes
1answer
606 views
how does division occur in our computers?
How does division occur inside the computers ? What is the algorithm for it ? I have searched hard in google but haven't got satisfactory results. Please provide a very clear algorithm/flowchart for ...
0
votes
2answers
134 views
mapping non existent addresses?
"In terms of this picture of mapping addresses from the address space onto the actual memory locations, a 4-KB machine without virtual memory simply has a fixed mapping between the addresses 0 to ...
3
votes
2answers
503 views
hardware implementation of division algorithm
I have tried hard but I don't understand how this algorithm is working.Please explain the flow chart.
\$DVF\$ is the divide overflow flip flop.
\$A_s\$ is the sign bit of \$A\$
\$B_s\$ is the ...
0
votes
2answers
138 views
what happens when the carry bit is zero in addition/subtraction algo for hardware
This is the algorithm in flow diagram for addition and subtraction in computers.
A(s) is the sign bit of A
B(s) is the sign bit of B
//(s) denotes the subscript
E is the register that has a ...
1
vote
3answers
307 views
address field and words of memory
"Consider as an example a typical computer of that era which might have had a 16 bit address field in its instructions and 4096 words of memory.A program on this computer could address 65536 words of ...
0
votes
0answers
78 views
Miniature computer with wifi, audio support needed [closed]
I'm looking for the simplest possible miniature computing device that would be programmable, and has support for wireless networking and audio.
Ideally, this thing would:
Run GNU/linux or some ...
1
vote
1answer
144 views
Why is it that disk storage has increased exponentially over the years, while disk access times barely improved?
If you look at how much we are able to store on our disks these days, you'd be appalled to notice that the time required to access information from the disks have grown very insignificantly compared ...
1
vote
4answers
1k views
Can a Computer Motherboard Speaker/Buzzer output voltage switch a relay?
Most 12v relays I've come across require 4v to switch on. I don't have a voltmeter handy to test my computer motherboards voltage output, and if it did give out +4v and held a long enough duration ...
0
votes
3answers
369 views
RS232 which pin i can connect together to receive a input signal in my Java application listening on ttyUSB0 or ttyS0?
I am trying to make a very simple BUTTON (simple wire RED/YELLOW only). Now if the Button is pressed (RED touch YELLOW) i want to receive input signal in my Java application (that button was pressed).
...
2
votes
3answers
195 views
Charging marine battery while powering equipment
I've got a quite delicate setup with a PC and some other minor equipment such as a microcontroller connected to a large 100Ah sealed (AGM) 12v lead acid battery.
I need to be able to run my equipment ...
1
vote
2answers
211 views
What is this component(pic)?
It's the one dead center of the circle that exploded. I was thinking it was either a diode or a capacitor of some kind, but I don't know how to tell its value from its markings. This picture is of a ...
13
votes
3answers
1k views
Explain what is a transistor in plain English!
Can someone care to explain - in plain English - what a transistor is and how it works. I know computers are full of these but don't know much about them.
P.S. I know about this site from another one ...
2
votes
2answers
1k views
How to make my own atx power switch?
I'm assembling a new computer from components. It's something I've done quite a few times, but now I would like to skip the case. Except for some structural integrity and LEDs, the only technical ...
-6
votes
4answers
2k views
How to build a custom laptop computer with original chassis, keyboard, etc? [closed]
I'm interested in building a custom laptop computer with the hope of being able to sell it and make a profit. The only problem is I have no idea where to start. I have an idea for a laptop chassis ...
5
votes
6answers
4k views
How can I send data to the arduino from the computer?
How can I send data to the arduino from the computer? I'm thinking sort of a prompt on the command line and some commands like "led1 on". Then, the arduino would process that and light up a certain ...
1
vote
2answers
217 views
Connecting a high-speed comparator into a computer
I need to store the output of a stand alone comparator (Hittite HMC875LC3C) in computer RAM drive. Currently, I'm using an 8bit 2GHz ADC (an Agilent PCIe - Acquiris U1071A) to bridge between the ...
1
vote
3answers
761 views
CPU considerations for PCB software (routing) when purchasing a new computer
My company uses Altium Designer for PCB design and the most CPU intensive operation seems to be the autorouting.
My question is, when considering a new computer, would it benefit autorouting ...
4
votes
1answer
2k views
What is the purpose of an IO shield on a computer case?
What purpose does the IO shield on computers serve? I have been reading a lot of articles (mostly forums) on the internet and can't seem to find a definitive answer.
1
vote
3answers
495 views
Where to find 478 motherboard circuit schematics?
I have searched for 478 motherboard circuit schematics on the internet, but have found none. Are any available publicly?
4
votes
2answers
285 views
Single-board computer
I am researching some embedded applications that will leverage the use of a single-board computer (SBC). I am looking for a SBC that has a very small form factor, supports wireless networking, and can ...
1
vote
1answer
260 views
Microcontroller board with ethernet for computer sensors
I'm considering the possibility of using an ethernet-connected (SNMP would be a bonus) microcontroller board of some sort to monitor a RAID card inside a server that doesn't have OS support; the card ...
3
votes
1answer
180 views
Pros/Cons of different backplane architectures?
Are there some general resources (other than spec sheets of boards) to compare the differences between computing formats like VPX, VME, IBM bladecenter-h, etc?
I am tasked with doing some legwork ...
3
votes
6answers
439 views
Connecting landline to soundcard
I'd like to connect my landline tellephone to my computer's soudcard, and I was about to do this when somebody warned me that the voltages are all wrong and that I will blow my soundcard.
To what ...
5
votes
5answers
5k views
Computer controlled water valve
I'm working on a computer-controlled indoor waterfall. One of the requirements is to be able to change the water pressure via computer interface. I've googled all day long and can't seem to find a ...
12
votes
4answers
8k views
What are different types of computer architectures?
I am going through the book "Elements of computing systems". This book teaches how to build a whole computer from scratch. While I was just browsing the chapters on computer architecture, I noticed ...
7
votes
6answers
1k views
Can you base a computer around a 32-bit microcontroller?
We all have(mostly) 32-bit machines at our homes. But the 32-bit machines have a microprocessor in them. I was reading an article about the ARM Cortex. Its a 32-bit microcontroller. Now that intrigued ...
4
votes
3answers
798 views
Non-metal cases
This question is really aimed at computer cases, but I suppose it also applies to other PCB cases. Most of the Computer cases I come across are aluminium, or else some other metal; As I understand it ...
9
votes
5answers
1k views
What are some of the more compelling use cases for plug computers?
Are plug computers useful for anything besides network-attached storage?
I know that you can hang a bunch of drives off them, maybe set up your own web server. But those uses have limited ...
12
votes
5answers
6k views
Reusing laptop monitors
I have a 17" laptop monitor with a 1920x1200 (WUXGA I beleive it's called? or just UXGA?) resolution which I simply love. Now, assuming the laptop dies before the monitor does, would anyone know if it ...
