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1500 questions
95
votes
10 answers
Why are there no 256-bit or 512-bit microprocessors?
In an 8-bit microprocessor its data bus consists of 8 data lines. In a 16-bit microprocessor its data bus consists of 16 data lines and so on.
Why is there neither a 256-bit microprocessor nor a 512-bit microprocessor? Why don't they simply…
Michael harris
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94
votes
10 answers
How to get more than 100mA from a USB port
I heard that the current limit for a USB port is 100mA. However, I also heard that some devices can get up to 1.8A from a port. How do you get past the 100mA limit?
200ok404notfound
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94
votes
11 answers
Is there a correct resistance value for I2C pull-up resistors?
The datasheet of the 24LC256 EEPROM states that:
The SDA bus requires a pull-up resistor to VCC (typical 10 kΩ for 100 kHz, 2 kΩ for 400 kHz and 1 MHz).
I thought that any resistor with a kΩ value would do the job (and it seems that my EEPROM…
JonathanD
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92
votes
4 answers
What are the different types of solder used for?
How do I know when to use lead, flux-core, lead-free, or any other kind of solder out there? Do you have any tips on solder gauge for specific applications?
cmchap
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91
votes
12 answers
How can I tell the size of a barrel power connector?
Spring cleaning, and I'm trying to get power supplies for all my devices with missing power supplies. They're all the typical barrel power connector, and I'm having a dickens of a time trying to figure out the pin/hole diameter.
I ordered the…
dwwilson66
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91
votes
6 answers
What is the difference between a DSP and a standard microcontroller?
I understand that a DSP is optimized for digital signal processing, but I'm not sure how that impacts to the task of choosing an IC. Almost everything I do with a microcontroller involves the processing of digital signals!
For example, let's…
Kevin Vermeer
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91
votes
11 answers
Can you make a non-polar electrolytic capacitor out of two regular electrolytic capacitors?
There was some discussion on this question
What are some reasons to connect capacitors in series?
What are some reasons to connect capacitors in series?
which I don't see as being conclusively resolved:
"turns out that what might LOOK like two…
endolith
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90
votes
19 answers
How do I prove to my physics teacher that adding a battery in parallel doesn't double the current?
simulate this circuit – Schematic created using CircuitLab
My physics teacher said that the current through the resistor is 4A because each battery has a current of 2A if hooked up to the resistor on its own, and so they both have 2A of current…
Student
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90
votes
7 answers
What type of solder is safest for home (hobbyist) use?
I'd like to do some hobbyist soldering at home, and would like to make sure I don't poison those living with me (especially small children). Lead-free seems necessary - what other features should I look for in solder? Are the different types of…
Matt B.
- 3,805
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88
votes
6 answers
Looking for circuit board material that can be dissolved
We are working on a product where the entire device needs to be dissolved in liquid after the device has operated and the device is no longer usable or desired.
This is a down-hole application. The device body is either aluminum or magnesium. …
Dwayne Reid
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88
votes
12 answers
Where does electricity go after being used?
For a very long time I have been wondering, where does electricity go after being used? When I use my tablet it runs from a battery. Where does the power go?
Ethan T.
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88
votes
5 answers
Relay vs. Transistor?
Rather basic, I'm afraid, but when would you use a relay, and when would you use a transistor? In a relay the contacts wear out, so why are relays used at all?
hauntsaninja
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87
votes
8 answers
When is a MOSFET more appropriate as a switch than a BJT?
In my experimentation, I've used only BJTs as switches (for turning on and off things like LEDs and such) for my MCU outputs. I've been repeatedly told, however, that N-channel enhancement-mode MOSFETs are a better choice for switches (see here and…
Mark
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86
votes
5 answers
How much current can I draw from the Arduino's pins?
What's the maximum amount of current which I can draw from each of the Arduino's pins without tripping any of the internal fuses? Is there a limit per pin as well as an overall limit for the whole board?
berry120
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86
votes
7 answers
What is the relation between FFT length and frequency resolution?
If I have sampled a signal using proper sampling methods (Nyquist, filtering, etc) how do I relate the length of my FFT to the resulting frequency resolution I can obtain?
Like if I have a 2,000 Hz and 1,999 Hz sine wave, how would I determine the…
Kellenjb
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