Questions regarding architectures or design of specific parts, not consumer-related questions.

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2answers
154 views

How to control the current output from usb slots of computers?

Is it possible to control output from a computer usb port so, for instance if I have a usb led I can make it blink or do whatever with it. Whenever I send a high signal it would glow and whenever I ...
1
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1answer
207 views
+50

Micro and Nano Memory, Calculate Reducing Bits?

I ran into a question: in digital system with micro-programmed control circuit, total of 32 distinct pattern operation signal is ...
0
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1answer
23 views

Which are the spec bits in this cache?

I have a direct mapped cache of size S with the line size L. The cache is physically indexed and tagged. The physical address is 50 bits, numbered from 0 to 49 (with 0 being the least significant ...
0
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1answer
16 views

What is the difference between a virtually tagged and a physically tagged memory system?

I study computer architecture and this question came. What is the difference between a virtually tagged and a physically tagged memory system?
1
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0answers
39 views

What GPUs have a datasheet?

I am trying to make my own video card for a homebrew computer, and I need to figure out which GPU to use. The problem is, the ones I have managed to salvage - a Savage MX, ATI Radeon 9000, and some ...
3
votes
1answer
60 views

adding two 64-bits number with m-bit carry ripple adder and multiplexer, a questions?

I ran into a question from computer architecture class. The professor says that for adding two 64-bit numbers A and B we use m-bit carry ripple adders and multiplexers such as following: and that ...
0
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0answers
21 views

Use Mosfet to switch secondary Powersupply on

I'm building a small computer that uses a Thin M-ITX motherboard. But I'm also using an GPU that is being powered by a secondary board. This secondary board has a regular 24-Pin ATX header. I know ...
0
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1answer
64 views

RPM v read/write speed

I am a developer using languages like C++ and .NET. I am trying to understand how computers work at a lower level. Say I have a hard disk that is 7400RPM and 150MB read/write speed. My book implies ...
2
votes
2answers
75 views

Using a toggle switch to act as push button

Basically I want to use a toggle switch to turn on my computer. I need some sort of circuit so that the toggle switch will act like a push button. IE, I turn on the toggle switch but it only sends a ...
0
votes
1answer
109 views

Reduce 160 Volts AC to 100 - 110 Volts AC (EL Wire Tape) Help

I am trying to put EL Wire Tape in a project that I am working on. I decided to go and build an inverter for 12VDC to 100VAC and that fell through. I couldn't find any guides that helped on EL Wire ...
-2
votes
2answers
153 views

Where is the best place I can go to learn everything about the electronics-side of computers? [closed]

Throughout my childhood, I grew up learning about electronics and computers. I am starting to get to the point where I want to incorporate my knowledge of both into a single project. I have tried ...
2
votes
2answers
66 views

Detecting TVs with PC's graphics card

I'm interesting of how can graphics cards detecting what type of TV has connected with S-Video? TVs sent some indefiniter signal back to the computer? And how it's working (protocols, signals, freq, ...
2
votes
3answers
141 views

Is hardware flow control necessary?

I want to communicate using a serial cable to a device that uses RTS/CTS flow control and 115200 baud speed. I want to use this Sparkfun TTL to rs232 adapter, but it has no RTS or CTS pins. What can I ...
0
votes
2answers
205 views

Can we observe addresses, data and other signals on the microcomputer buses by an oscilloscope, a LED or even an ordinary DC voltmeter?

Microcomputers are dynamic devices that are synchronized by a clock oscillator. So the signals (E, R/W, CS, A15-A0, D7-D0...) appear on their buses only for parts of a microsecond and, as the buses ...
0
votes
1answer
105 views

What is the purpose of the thick blue line in this schematic?

On this schematic for a Z80 computer, there appears to be a thick blue wire connecting some components together. What is it? Googling yields no results: here is the schematic
0
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1answer
195 views

Determining memory address width from memory size

Given a computer A with 1024 x 16 memory and a computer B with 16K x 32 memory, how big are the registers of an Accumulator, program counter, instruction, temporary register, address register, data ...
2
votes
3answers
89 views

Curious how does ALU addressing work like in Assembly code?

When writing assembly code, say R1 = R2 + R3, it is pretty easy to understand the addressing procedure because all registers are close to the ALU. But I find it hard to see how does the ALU go to the ...
1
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0answers
52 views

Design considerations for internal PC parts

I'm designing a PWM fan controller. It will be interally mounted inside a PC and will take power from the normal 4 pin Mate-N-Lock ("molex") connector. The on-board MCU and LCD will draw power from ...
0
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0answers
118 views

Can a zener diode be used to slow down a fan?

I often use a resistor to slow down a fan in older PC's, because these old computers are too noisy. Can a zener diode be also used to slow down a fan in a PC? As far as I know these small fans are ...
1
vote
1answer
118 views

How much RF-interference does a typical desktop computer produce? How much does a metal case without windows reduce it?

It's fairly common now to see desktop computers in cases with large windows cut in the sides. I've always been under the impression that if unshielded, computer equipment will produce a lot of radio ...
-1
votes
1answer
121 views

Parallel MAC unit based on modified booth algorithm

The below diagram is the parallel MAC structure. In parallel MAC both partial product addition and accumulation take place at same time. The partial product summation + accumulation unit of above ...
2
votes
1answer
271 views

What was the crysistor?

I'm reading through Jim Williams' "Analog Circuit Design: Art, Science and Personalities", and a mysterious component called a crysistor is mentioned. There are a few clues in the text, like the fact ...
1
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1answer
58 views

How do you reduce an 8 output ALU to a 4 or 3 output ALU?

I can implement the functions in the picture below, but then if I implement them independently, I would have 8 outputs to the mux. Our professors wants us to reduce the ALU to only 3 or 4 outputs, I ...
1
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2answers
394 views

How are microscopic transistors on microchips made?

How is something like a microchip which is already small as it is able to house even smaller transistors in the millions at such a micro-scale? It seems like such a feat for machine to be able to make ...
0
votes
1answer
94 views

What determines the maximum rotational speed of a hard disk drive?

Through my background research I understand that the limit on the rotation of a hdd is largely the product of heat and the specs of the physical disk, but I am puzzled by the round numbers advertised ...
0
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2answers
86 views

Average Cycles Per Instruction

We have two different computers with the same instruction set. There are three classes of instructions (A, B, and C) in the instruction set. Computer M1 has a clock rate of 80 MHz and Computer M2 has ...
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votes
2answers
130 views

Where does power in my laptop go when I disconnect the battery? [closed]

I have a laptop which, when put to sleep, sometimes enters a state of limbo, from which it can be neither turned off nor on, and the only solution is to disconnect the battery, reattach it, and turn ...
-1
votes
1answer
658 views

Design and build a single board computer [closed]

I want to learn how to design and build a single board computer like the Raspberry Pi. I saw a DIY project on Hack-A-Day and design something like the board in the DIY project but a bit more ...
0
votes
1answer
78 views

Safely shutting down 19V mini PC when power fails

I am adding an Intel NUC (4"x4" i5 PC, 12-19V, 10A@19V) to my guitar effect pedalboard for all kinds of fun signal processing with Ableton Live and Max/Msp. I'm building a 12V 20A power supply using ...
0
votes
3answers
134 views

How hot can MOSFETs get before blowing up?

This is different from a lot of other stuff here, but I have a motherboard that has no MOSFET cooling, and when I touch them they burn my hands; they are probably 70-80C. I just want to know how long ...
0
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0answers
94 views

Interpolate DDR3 timing from DDR3-1600 to DDR3-1866?

This is an interesting math + electrical engineering problem. I have DDR3-2133 memory but it had presets for DDR3-1600 and DDR3-2133 but the fastest my motherboard supports is DDR3-1833. That means I ...
1
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3answers
165 views

What exactly does a 10-transistor XOR gate look like?

I need a schematic for a 10-transistor xor gate, I have searched everywhere and I see 8, 12, 6, but I can't see 10. What does it look like in a transistor like picture?
3
votes
2answers
179 views

Switch on computer with microcontroller

I'm making a simple microcontroller based circuit to turn on a computer when certain events are triggered. I am interfacing it using the PCs soft power switch pins on the front panel header: There ...
0
votes
1answer
523 views

Repairing (possible) earthing/ground issue in computer PSU? [closed]

I've got a computer that will no longer power on. It used to be willing to power on quite randomly, and ran fine when it did. I'm not an electronics savvy person, but i've done a manual check on the ...
1
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2answers
175 views

Complexity involved in building a single board computer [closed]

Our high school has tasked my and a friend of mine with with building a web connected controller for a hydroponics system. The school has budgeted 5k for us to spend as we like, and we are intent on ...
1
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2answers
183 views

Why is a binary system used instead of decimal system when interpreting voltages? [duplicate]

In physical computing, binary is used to perform calculations. Typically, 1 corresponds to high voltage (3V-5V), and 0 corresponds to low voltage (0V-2V). Perhaps it is not feasible due to the ...
-3
votes
1answer
150 views

What does it take to design and manufacture a bespoke computer mainboard? [closed]

Consumer computer hardware evolves quickly: new models are replaced by even newer ones, but sometimes the design takes direction that some portion of users just cannot accept; models or entire ...
-2
votes
2answers
90 views

How many people might have been involved in the design of the Macintosh SE? [closed]

It is really difficult for me to know how many people were in charge of the development of this electronic wonder. When I'm struggling to properly comprehend transistors and how they work, these ...
1
vote
1answer
449 views

Why does Intel produce core i3, core i5 and core i7 processors; but not core i2, core i4 or core i6 processors? [closed]

Why does Intel produce core i3, core i5 and core i7 processors; but not core i2, core i4 or core i6 processors? What is the reason behind this?
-1
votes
1answer
75 views

Static in earphones when scrolling with mouse [closed]

Why do I sometimes hear faint static in my headphones when I scroll with my mouse? I have noticed this on multiple(4) computers, with Windows 7 and 8. Does anybody else notice this? It happens when I ...
-1
votes
3answers
202 views

Conductivity of plastic, wood and leakage current of laptops

Back around 2010, there were incidents where the surface of laptops have conducted 20-100V and have electrically shocked users. There is no doubt most of the newer laptops still conduct a continuous ...
0
votes
1answer
107 views

Can convection draw cold air INTO a PC case?

So imagine I'm mounting my nettop-style PC behind my monitor. Its CPU is passively cooled via heatsink. Now the side facing up should have vents so the warm air can escape the case but shoud the side ...
1
vote
3answers
268 views

Ways to connect a PCIe/PCIe2 card and other PC parts to a breadboard?

Basically I have a bunch of rather old computer parts that I haven't been able to get rid of so I decided to do a few experiments with them but for that I need to be able to breadboard them. Things ...
1
vote
2answers
261 views

PC to Arduino wireless link (low latency)

I want to build a robot car with an camera gimbal on top of it. This robot and gimbal should be controlled wireless by a gamepad and the head tracking of an Oculus Rift. As it is with the Oculus Rift, ...
1
vote
3answers
244 views

Is a digital bit represented by any two discrete signals?

I am trying to understand computers from the building blocks up. I know computers use transistors to amplify voltages, and this is used for arithmetic, such as a MOSFET. However, what really makes ...
0
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0answers
72 views

Are there any registers that are read_clear in PC devices?

As we know, in x86 PC devices, there are some kinds of registers that are write_clear, that is, if we write "1" to the register, the register will be cleared. So I want to know if there are any ...
0
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5answers
1k views

Is powering a sound system from a computer's power supply a bad idea?

While this answer over on Super User looks like it would work, would it be bad for the computer power supply to be the power source for a sound system? Would it cause power fluctuations that would ...
4
votes
2answers
776 views

Homemade ethernet hub not working with three computers [closed]

I am trying to connect three computers in one network. I have connected the wires like the photo. I works with two computers but not three computers at the same time. For example, let's name the ...
3
votes
2answers
604 views

How to combine PC's power and HDD LEDs?

I'm going to buy a PC tower case which has only one LED intended to be used as the power LED, thus no HDD LED is available. My intention is to have that single LED at about 50% of its intensity when ...
4
votes
8answers
285 views

Why can computer circuits recognise only two states?

Computers can only understand binary (that is 0s or 1s). I want to know Is there any way that computers can understand more than 2 states. I know that It is much harder to build components that use ...