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1500 questions
49
votes
18 answers
Which electronics components should I always have on hand?
I am thinking about ordering up some parts for every day use. I am thinking about making one big purchase so as to minimize on shipping and other charges.
What are some of the components that any electronics hobbyist should have around ALL the…
jdiaz
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49
votes
9 answers
Can an FPGA design be mostly (or completely) asynchronous?
We had a very short FPGA/Verilog course at university (5 years ago), and we always used clocks everywhere.
I am now starting out with FPGAs again as a hobby, and I can't help but wonder about those clocks. Are they absolutely required, or can an…
Roman Starkov
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49
votes
13 answers
How to go from newbie to manufactured?
I'm a software guy who wants to get into the hardware side of things so I can enjoy the same creativity from software design in the physical world.
I've found plenty of posts here regarding how to get "up and running" in the electronics world, but…
DJ_R
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49
votes
4 answers
Why do fire and security systems run at 27.6 V?
I have been looking at buying power supply units for a project, and I keep seeing supplies that output 27.6 V. It's an unusually specific number, so what they are used for, and why is it important that they produce 27.6 V?
It appears that these are…
Lucas
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49
votes
1 answer
How can I implement regenerative braking of a DC motor?
I know that many electric cars are able to convert the momentum of the car into stored energy in batteries, rather than convert it to useless heat at the brake pads. How does this work? How can I implement it myself?
Phil Frost
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49
votes
13 answers
Why do fundamental circuit laws break down at high frequency AC?
We're just starting the whole RF scene having dealt with DC and low frequency AC for all our previous courses.
I understand that at high frequency AC, fundamental circuit laws don't apply anymore and the classic passive component models need to be…
AlfroJang80
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49
votes
5 answers
Regulated 3.3V from a Lithium-ion (or LiPo) battery
Background
I wish to power my circuit with a Lithium-ion or LiPo battery (likely a battery with around 1000 mAh capacity). These batteries have a voltage that goes from 4.2V to 2.7V typically during their discharge cycle.
My circuit (running at…
boardbite
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49
votes
3 answers
Why are vias placed this way on a PCB?
I used to check complex commercial PCBs specially those of graphics cards to see how professional PCB designers do their layout and learn from their techniques.
When I checked the card shown below I noticed two things regarding the placement of…
Abdella
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49
votes
1 answer
What are the differences between a gyroscope, accelerometer and magnetometer?
What is the difference between a 3-axis gyroscope, 3-axis accelerometer and 3-axis magnetometer? How do these sensors work? Why are all 3 used in some devices like smartphones, tablets, quadcopters etc.?
Kicsi Mano
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49
votes
11 answers
Why isn't stripping wires by burning with a lighter a more common practice?
I see people suggesting specialized tools, or trying it manually with sharp knife or scalpel, why not just burning the rubber for a second or two with a lighter and just pulling it out a more suggested option?
Is there any con to this approach that…
appwizcpl
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49
votes
4 answers
Why does TI have so many microcontrollers?
I am working on a project with a group and I am responsible for the digital part of the project, so I will be writing the code. To go from Analog to Digital, I have to choose a microcontroller.
I was looking at TI microcontrollers and found that…
Andy_A̷n̷d̷y̷
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49
votes
6 answers
MOSFET as a Switch - When is it in Saturation?
I have the following circuit hooked up on a breadboard.
I vary the gate voltage using a potentiometer. Here is what confuses me: according to wikipedia, the MOSFET is in saturation when V(GS) > V(TH) and V(DS) > V(GS) - V(TH).
If I slowly increase…
Saad
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49
votes
2 answers
What is the ppm in the crystal oscillator?
I'm a student and I'm working on a low power communication project. I am trying to design a PCB using the TI CC2540 sample design. There is a MC-306 (32.768kHz, 12.5pf, and 20/50ppm).
I don't know what the 20/50ppm rating is. For me, the size is…
Mokus
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48
votes
6 answers
How do I model an LED with SPICE?
What diode modifiers are used in practice to model LEDs with SPICE (Berkeley v.3f5)? These are available to me:
# Name Parameter Units Default Example Area
1 IS Saturation current A …
tyblu
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48
votes
9 answers
How were the first microprocessors programmed?
This has just dawned on me that if you're writing an operating system then what are you writing it on? I ask this as I am reading a microprocessor fundamentals book from 1980 and this question popped in to my head:
How was the first microprocessor…
Dean
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