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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
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
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
2 answers
What is wrong with my 50 Ω grounded coplanar waveguide?
I've been working on a 4-layer design built around the EFR32BG13 Bluetooth Low Energy SoC. While trying to measure the impedance of the antenna to build a matching circuit, I discovered that my short grounded coplanar waveguide (GCPW) transmission…
Michael Cooper
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49
votes
5 answers
Why do 1 pF capacitors exist?
What kind of uses do engineers find for 1 pF or lower-value capacitors?
This is the kind of value one gets with two bits of wire close to each other or two tracks.
Dirk Bruere
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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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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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48
votes
3 answers
Why do we connect a battery to ground when jumping a car?
This may seem like a very simple question, but I've searched all over the place and haven't found an answer.
When jumping a car, we connect the + end of the charged battery to the + end of the dead battery, and the - end of the charged battery to…
Ken Levinski
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48
votes
2 answers
Why don't electrons take the shorter path in coils?
Below is a copper coil, presumably forming an electromagnet. From my understanding the electrons travel around the coil to produce a magnetic field. But why don't the electrons jump the wires and take the shortest path?
Below I tried to draw the…
rrswa
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48
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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48
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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48
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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48
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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