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1500 questions
26
votes
7 answers
How do I open a rectangular hole on a metal case?
I'm working on a case design. There is rectangular switch. I am trying to open a rectangular hole on the metallic case to fix it in there. I'm not doing a good job, if it goes on like this it looks like I'm going to ruin the case at all.
How do I…
hkBattousai
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26
votes
6 answers
What not to do with a Multimeter
So I just bought and installed a new fuse for an analog multimeter I scored for free and now it works like a charm. The new fuse is the same rating as the blown one I found inside, which is 0.5A 250V. The meter has a warning symbol consisting of…
Alex W
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26
votes
1 answer
Why must some HDMI repeaters know the cable length?
I just bought an HDMI repeater and had connectivity issues until I realized the repeater had to know the cable length. It has (1,2,4,8) dip switches that you have to use (binary coded) to set the cable length.
What I'm wondering is: How is the cable…
Jeffrey
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26
votes
4 answers
Can silicone sealant be used to insulate and waterproof electronic components?
Well, can it, when it is in direct contact with the components and circuitry?
slashmais
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26
votes
4 answers
How does Windows know it's on battery power?
Laptop DC-DC regulator boards are somehow able to communicate with Windows to see how much battery power is left, but my research finds nothing.
Is there a data connection from the proprietary motherboards found in laptops which communicates this?…
Rob
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26
votes
8 answers
Is it possible to receive information if the received power is below the noise floor?
This relates to my previous question, which I think I have asked in the wrong way:
How to insert background EM noise into pathloss equation?
I wasn't really interested in detectability of the signal, and I have phrased that question very…
David K.
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26
votes
5 answers
What exactly happens to the signals hitting a common mode choke?
I'm trying to better understand the principles behind the common mode choke. I made a few drawings to clarify.
Differential Mode Signals
Differential currents (driven by differential voltages) create equal but opposite magnetic fields B in the…
K.Mulier
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26
votes
5 answers
Fuses: What are the practical differences between Ceramic and Glass cartridge fuses
What are the practical differences between ceramic and glass tube cartridge fuses?
I am trying to find new fuses for a piece of consumer electronics. The original fuses are going out of production.
The fuses the original BOM called for are ceramic…
Connor Wolf
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26
votes
3 answers
How do the tiny AC->USB power supplies work?
The iPhone and Kindle both come with tiny power supplies that take in 120v AC and output around 5V at 0.85 to 1 amp. They seem to be too small and light to have a transformer, and generate very little heat. What is the electrical topology of these…
ObscureRobot
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26
votes
4 answers
VHDL that can damage FPGA
I read somewhere that bad VHDL code can lead to FPGA damage.
Is it even possible to damage a FPGA with VHDL code?
What kind of conditions would cause this and what are the worst case scenarios?
ESD
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26
votes
1 answer
Choosing the right transistor for a switching circuit
I want to control a siren speaker (has a built-in driver) with an Arduino.
The siren needs 12V and consumes about 480mA.
The Arduino output pin is 5V and can source 40mA maximum.
I would like to use a transistor to switch the siren on and off. Is…
darkadept
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26
votes
5 answers
What is dual/quad I/O?
Reading an SPI Flash datasheet, I encountered the concepts of "dual I/O" and "quad I/O". At first I thought that "dual I/O" was synonymous to "full duplex", but then what is "quad I/O"?
What is dual I/O and quad I/O, and how do they compare do…
Randomblue
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26
votes
1 answer
What is the STM32 event EVENTOUT?
In the manual of my STM32, one of the GPIO Alternate Functions (namely AF15, see page 138) is called EVENTOUT. At no point is the event defined, or a use case given.
What is the EVENTOUT alternate function of my STM32?
Randomblue
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26
votes
3 answers
Does Wi-Fi radiation pass through my body?
I'm curious. I think I'm confused because I don't really understand the way ionizing radiation works.
So the Wifi radiation passes through my body, but has no ionizing effects within my body?
Frank
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26
votes
3 answers
How do hotswapping computer parts work?
Computers support hotswapping so that a user can replace a harddrive while the system is running. Is that mostly software just powering off the harddrive or is it some special hardware involved? If there were not special hardware then I suppose that…
Niklas Rosencrantz
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