Questions tagged [alignment]
12 questions
9
votes
3 answers
PCB enclosure tolerances
I can imagine problems of PCBs not fitting into their enclosures or misaligned screw/hole pairs. Are these type of problems common, especially with the dirt cheap enclosures?
I am planning to use one that has a "0.8 mm tolerance". It does not…
kellogs
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8
votes
1 answer
Centroid of component for pick and place machine using Eagle
Just finished designing a PCB and sent the Gerbers off to my board house (Bittele) and they have requested that I also provide them with a pick and place file.
Using Eagle, I ran mountsmd.ulp and generated a pick and place file for my board.
Looking…
macdonaldtomw
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2
votes
1 answer
Custom Memory Allocator - How to find the required alignment for a platform?
I'm building a portable arena allocator for embedded systems.
Like for malloc, one of the requirements is to return a pointer aligned with the memory.
The question is: Is there a way to know at compile time what are the memory alignment requirements…
gbt
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1
vote
1 answer
Sensorless BLDC motor alignment methods
I have been trying to make a FOC for BLDC motor controlling, but I am stuck at the state that before open loop state which single alignment of the motor control. The question and the explanation is below :
I have applied 24V to the motor from a DC…
Semih Urtekin
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1
vote
3 answers
ON/OFF rocker switches - convention about which side should be top/bottom?
Is there a technical convention (maybe unofficial) as to which side to mount upwards ? I imagine there could be such a guideline, because the marking could rub off or users might have impaired vision.
I know this might attract opinions, but those…
tobalt
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1
vote
0 answers
GPS PPS Signal Duty Cycle?
just like the title says, I'm trying to figure out the duty cycle of a GPS's Pulse Per Second Signal.
This post and accompanying answers seem to indicate something like a 10% duty cycle:
GPS PPS signal corresponds to data time?
Whereas the waveform…
TimingConfusion
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1
vote
1 answer
How to tell flat flexible cable(FFC) alignment when inserting?
I have an MSR with an 8 pin FFC with contacts on one side. I don't know if there is a top and bottom and if so how to tell the orientation. There is writing on the contact side I assume to indicate alignment that looks like
<-
D1|
D2|
D3|
D4|
D5|
…
willpnw
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1
vote
2 answers
Aligning PCBA on a plastic enclosure
I am trying to align a PCBA very accurately (within +/- 0.5mm positional tolerance) on a plastic enclosure. I'm thinking about using two 2mm diameter dowel pin that is press-fitted into the plastic enclosure and then having the two clearance holes…
Philip C
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0
votes
4 answers
Why does unaligned memory read require extra clock cycles?
I believe I understand how memory reads work with the 8086 processor.
The 8086 has a 20-bit address bus and 16-bit data bus (multiplexed).
The memory module consists of two memory banks, and the LSB of the address bus is used to select which bank to…
obe
- 117
- 5
0
votes
1 answer
How are complicated PCBs designed?
Firstly, I've always wondered how do engineers calculate the right parameters of components (caps, resistors, inductors, ...) in big projects, such as mobile motherboards and etc.
It feels rather complicated and very time consuming, let alone error…
krlc
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- 2
0
votes
1 answer
Audio amplifier alignment procedure questions
I have a couple of questions related to the alignment procedure for the amplifier of Klipsch SW-12, a powered subwoofer.
Its service manual (link below) says the following:
(page 3)
COMPRESSION
The compression circuit consists of U5, U6, and Q28 and…
zeron
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0
votes
1 answer
How can I align chips on PCB?
I am searching for a method/device for aligning chips with pins/pads underneath, like QFN, LGA, BGA and others. I've been searching the Internet, but I could find anything except expensive (several k€) chip alignment machines.
Is there a…
Cristian M
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