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1500 questions
63
votes
4 answers
JTAG vs SWD debugging
After skimming through this article, I am wondering what are the benefits of SWD debugging over JTAG debugging?
I understand SWD uses less wires/pins, takes up less space etc. But how does it play out in terms of performance, features and cost of…
josef.van.niekerk
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63
votes
6 answers
What is the voltage range of a standard headphone jack from a phone?
I want to connect the output from the audio jack of an iPhone to an Arduino.
What voltage range can I expect to see on the audio lines from the iPhone? I assume that turning the volume up on the phone will produce a large AC voltage, but how large…
manuelBetancurt
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63
votes
1 answer
What are these boxes mounted inline on each of the 3 phase wires of a high voltage power line in Miami?
They were only on this run and not any of the lines in the area. And what is the function of the flat u-shaped guards in front of each?
bigjosh
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63
votes
9 answers
How do I saturate an NPN transistor?
I understand that in "saturation mode", a BJT functions as a simple switch. I've used this before driving LEDs, but I'm not sure I understand clearly how I got the transistor into that state.
Does a BJT become saturated by raising Vbe above a…
Mark
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62
votes
3 answers
Is this video fake? I thought Tesla coils only worked on AC
This video shows a 9-volt battery connected to a wire as a primary.
The first reason I think this is fake is that he is powering a Tesla coil with 10 volts.
The second reason is that Tesla coils work on AC, or at least I thought so, and he wouldn't…
Gabriel ashmore
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62
votes
8 answers
How do I go from an Arduino on a breadboard to creating a real device?
My first Arduino project: I have made a headlight sensor that will activate an outside light when a car's headlights hit it. I know I could go buy one, but where is the fun in that?
Now I would like to make a "real" one to mount outside my house so…
Steve
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62
votes
7 answers
Why are there teardrops on PCB pads?
What's the use of the teardrop shapes around some PCB pads?
Federico Russo
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62
votes
5 answers
How can an FPGA outperform a CPU?
I hear of people using FPGAs to improve performance of systems that do things like bit-coin mining, electronic trading, and protein folding.
How can an FPGA compete with a CPU on performance when the CPU is typically running at least an order of…
David Gardner
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61
votes
3 answers
What is the latency of an LED?
LEDs are known to have a very low, unnoticeable power-cycling latency, but how fast are they when measured? (nanoseconds?)
In other words, how long does it take for an LED which is entirely off to get to its optimum brightness, and how long does it…
ayane_m
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61
votes
6 answers
Why am I not dead after repeatedly touching a high-voltage source?
While playing with mosquito racket in my home, I unscrewed the racket and touched the 2 wires with my hands. I felt that my bones were dislocated, I got shocked, but I am not dead.
My calculations say that I should die:
the output voltage is 5 kV to…
pankaj prasad
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61
votes
10 answers
Why is main's neutral tied to earth?
My dad is an Electrician and I myself am an Electronics Design Engineer, and to this day he still hasn't been able to give me a good reason for this.
Consider the two following pictures/situations - both the same case, but with neutral not tied to…
DSWG
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61
votes
3 answers
Noise and what does V/√Hz actually mean?
Noise figures in (op-amp) datasheets are expressed in V/√Hz, but
Where does this unit come from? Why the square root? How should I pronounce it?
How should I interpret it?
I know lower is better, but will a noise figure that doubles also double the…
jippie
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60
votes
2 answers
"Remove After Washing" on Piezo Buzzer
Maybe this is a stupid question, but here goes:
I just got a piezo buzzer and on the top there is a sticker that says "Remove After Washing".
My question is why would I ever want to wash an electronic part? I have no idea. Is there some…
kmort
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60
votes
9 answers
RTOS for Embedded Systems
I have seen many articles that tell me I should be using RTOS for time management and resource management. My time has not permitted my own research, so I come to chiphacker for advice.
I use low resource microcontrollers(MSP430, PIC) and was…
Kortuk
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60
votes
4 answers
Why do we use 32.768 kHz crystals in most circuits?
Why do we use 32.768 kHz crystals in most circuits, for example in RTC circuits? What will happen if I use a 35 or 25 kHz crystal?
I assume because the IC internal Xin, Xout pin circuitry should be in CMOS/TTL/NMOS technology. Is it that true?
ramesh6663
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