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Questions tagged [standard]

For questions about technical standards such as IEEE standards. Examples of such questions include: what a standard requires, how to meet the requirements of a standard in a circuit design, what capabilities and limitations a circuit designer can assume when incorporating a standards-compliant component in a design, etc.

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332 votes
8 answers
171k views

Rules and guidelines for drawing good schematics

There are a lot of poorly drawn schematics here. A few times people have actually asked for critiques of their schematics. This question is intended as a single repository on schematic drawing rules ...
224 votes
7 answers
204k views

Why was Mini USB deprecated in favor of Micro USB?

Mini USB connectors were standardized as part of USB 2.0 in 2000. In 2007, the USB Implemeters Forum standardized Micro USB connectors, deprecating Mini USB connectors four months later. Why? What ...
Dan Fabulich's user avatar
  • 2,141
29 votes
4 answers
37k views

Standard nomenclature for component types

What prefixes should be used on reference designators for components of various types? I think we can all agree that "R##" refers to a resistor, "C##" refers to a capacitor, and "L##" refers to an ...
Kevin Vermeer's user avatar
21 votes
4 answers
2k views

Electronics System Standards Compliance: Certification, Testing & Verification

Please note: this question has to do with the technical compliance aspects of the consumer electronics indsutry, and as such, I believe is within scope for this site. This question is about compliance,...
smeeb's user avatar
  • 797
16 votes
6 answers
2k views

"Standard" components...?

In class we are designing a few different circuits and it uses some diodes and opamps. Everything is fine on paper and everything makes sense. These are only ever refereed to as a "diode" or "opamp". ...
binarysmacker's user avatar
16 votes
4 answers
27k views

What is a digital video port?

I see a few questions here casually mention that image sensor modules have a "standard parallel digital video port (DVP) or ... MIPI high-speed serial interface" "Where do I start with embedded video?...
davidcary's user avatar
  • 17.7k
15 votes
1 answer
2k views

Official GPS protocol documentation?

Searching for "GPS protocol" reveals many sources for processed GPS data, e.g. NMEA or binary outputs of GPS units. Where is the official documentation for the GPS satellite - receiver protocol? Or ...
Mark Harrison's user avatar
15 votes
8 answers
3k views

Is there a standard which requires a high voltage warning label on a PCB?

If part of your PCB carries high voltages at certain nodes, is there a standard that requires some sort of silkscreen label or sticker to warn technicians when installing/uninstalling boards into ...
BobaJFET's user avatar
  • 1,012
14 votes
3 answers
2k views

Standard Volt and Ampere

A recent question on here asking about how to calculate the accuracy of a circuit got me thinking about calibration in general. In particular, as EEs we routinely use volts and amperes as a unit and ...
Trevor_G's user avatar
  • 46.8k
13 votes
4 answers
3k views

How to read Scaled Graphs?

Please ignore the graphed lines, those are irrelevant to the question, it's the graph itself that's relevant. I see this type of graph used all the time, between ...
Passerby's user avatar
  • 73.2k
13 votes
4 answers
2k views

How were standard serial port baud rates chosen?

How were standard serial port baud rates chosen? 1200, 9600, 115200, aren't the numbers we'd expect (powers of 2 or 10), but don't seem random either. Wikipedia states Many of these standard modem ...
SRobertJames's user avatar
  • 1,121
13 votes
4 answers
6k views

How do you pronounce the following set of 'words'? [closed]

I've heard people pronouncing the following 'words' in different ways and I would like to know the correct way of pronouncing them. SPI (spy vs s.p.i) I2C (I.2.C vs I.squared.c) LED (lead vs L.E.D) ...
efox29's user avatar
  • 12k
13 votes
2 answers
1k views

‘One for all’ standardized land pattern v.s. specified land pattern in datasheet

I’ve designed lot of ‘simple’ PCBs for hobby and proof-of-concept purposes, but never for (mass)manufacturing. In order to do so in the future, and further expanding my design skills and knowledge, I’...
Julien Roels's user avatar
13 votes
3 answers
1k views

What is *actually* a *standard part*?

This is something that has bothered me for ages. I wasn't sure it could be made up as a question here, until Olin Lathrop suggested it to me in a comment to another thread. We all know what we are ...
LorenzoDonati4Ukraine-OnStrike's user avatar
12 votes
1 answer
3k views

What standard governs the dimensions of SMT chip resistors and capacitors?

I am aware of the JEDEC registered outlines, which define the standard mechanical dimensions and tolerances for a wide variety of solid-state packages. However, these standards do not appear to cover ...
SWB's user avatar
  • 333
10 votes
5 answers
2k views

What tools or standards can be used to improve embedded C code reliability?

I typically program PICs in C, usually for switched-mode converters. I've heard of various static analysis tools and standards like MISRA C that can be used to help improve the reliability of code. I'...
Stephen Collings's user avatar
10 votes
3 answers
11k views

North American standard symbol for ferrite bead?

Many of the schematics I've seen in reference schematics use an the symbol of an inductor as the symbol for a ferrite bead (makes sense). But I've also seen other variants of it as well. I don't have ...
efox29's user avatar
  • 12k
9 votes
3 answers
486 views

Is it safe to treat a system downstream of a reverse-biased diode as de-energized?

Suppose I have a 480 VAC line, feeding a rectifier and filter caps. Obviously this is not something to be trifled with while live. Now, suppose there are blocking diodes coming off the DC bus, as ...
Stephen Collings's user avatar
9 votes
2 answers
591 views

Medical electronic devices quality

Is there a special grade for electronic components made to be used in medical devices such as life support systems? I have read in most data sheets that "this product is not to be used in life support ...
User's user avatar
  • 849
9 votes
4 answers
4k views

Standard enclosure sizes?

I am working on a project and have decided that I will design the PCB so that it fits a standard enclosure size, as was suggested here. All electronics websites sell some variety of enclosures, and ...
rascher's user avatar
  • 983
9 votes
2 answers
4k views

Phasing Order in IEC Color Codes

Currently, IEC 60445 international standard is used for conductor terminal color identifications. I've obtained different versions of the standard (2017 being the latest) and also IEC 60446, which was ...
obareey's user avatar
  • 125
9 votes
1 answer
583 views

Are Ethernet (copper 10/100/1000) compliance tests mandatory?

The IEEE 802.3, for Gigabit Ethernet, and supposedly the ANSI INCITS 263*, for the Regular and Fast Ethernet, have lists of signal quality requirements, which are generally tested using the so-called ...
AndrejaKo's user avatar
  • 23.5k
8 votes
1 answer
3k views

Why are fast blow fuses more tolerant to small over currents than slow blow fuses?

I am looking at fuses from a cable protection standpoint. According to this doc the IEC standards for typical miniature fuses (IEC127-2) can be summarised as: Why can fast acting fuses tolerate a 210%...
sebf's user avatar
  • 553
7 votes
2 answers
444 views

What (if anything) are the standards for "generic" part numbers?

If I buy an MMBT4401 from Diodes, Inc., I get a 40V, 0.6A NPN transistor in a SOT-23 package. If I buy an MMBT4401 from ON semiconductor, I get a 40V, 0.6A NPN transistor in a SOT-23 package. If I buy ...
Hearth's user avatar
  • 35.1k
7 votes
1 answer
3k views

Does DIN rail have a weight limit?

Lots of industrial electronic hardware mounts to DIN rail. I would think there must be a weight limit to such mounting. But I haven't been able to identify one. Is there a defined weight limit, either ...
Stephen Collings's user avatar
7 votes
2 answers
1k views

Designing single fault safety into class I device

I'm trying to wrap my head around safety standards for electrical equipment. My device is medical, so for me section 8 of IEC60601-1 is what really matters to me, but it's kind of my understanding ...
deltamac's user avatar
  • 131
7 votes
0 answers
479 views

When exactly was the RS-232 standard issued? [closed]

This year is 50th anniversary of RS-232 standard. Despite its age it is still used nowadays, and I work in company that has to deal with it. So we have a half-serious idea to celebrate the exact day ...
aimozg's user avatar
  • 79
6 votes
3 answers
5k views

How low an insulation resistance is too low for a residential electrical system?

I have had occasion recently to test the wiring of a residential building for damage from a lightning strike. I opened all the breakers, removed all the loads, opened the panel, and meggered each hot ...
Stephen Collings's user avatar
6 votes
2 answers
230 views

Inspection/QA Criteria for Selling Electronics?

I'm a software developer who has recently taken up a penchant for home electronics and personal robotics. I'd like to start building a prototype for a small device that I would sell though a website, ...
HeineyBehinds's user avatar
6 votes
2 answers
2k views

Is there any generalized symbol for an electrolytic or electroplating cell?

Is there any symbol for an electrolytic cell? An electroplating cell, for instance? (There are commonly used symbol for electrochemical cell (battery symbol). But symbol for electrolytic cell not ...
user avatar
6 votes
2 answers
5k views

Reading noise from allan variance plot for MEMS sensor per IEEE Std 952-1997

I am following the Standard Sensor Performance Parameters from the "MemsIndustryGroup" to test some Gyroscopes: I conducted a test and plotted the square root of AVAR (Allan Deviation) against Time ...
MrHappyAsthma's user avatar
6 votes
1 answer
166 views

How to determine which harmonized standards are relevant to achieve CE conformity declaration

We are aiming to develop our first product to achieve a CE marking. So far i understand that there are a few directives like Low Voltage Directive (LVD), ROHS, EMC, etc, which can be implemented by ...
Jogitech's user avatar
  • 760
6 votes
2 answers
3k views

"Standard" Footprint for SMD Crystal [duplicate]

I want my design to use as many common footprints as possible (eg. 0805/0603 for capacitors and resistors, powerSO8 for big switching MOSFETs, etc) so that I am less restricted by manufacturers and ...
user371366's user avatar
5 votes
2 answers
1k views

If there is a cable and jack standard for I2C?

I want to do a connection of multiple current and voltage meters, they connect by I2C. Is for to monitor solar panels and batteries, they will be a considerable distance from the master. I thinking ...
DrakoPD's user avatar
  • 71
5 votes
2 answers
997 views

What standard defines the number of stop bits in RS-232?

There is an option in many terminal programs or ICs to set 1 stop-bit, 2 stop-bits or 1.5 stop-bits. Is there any standard that says the RS-232 can have only 1/1.5/2 stop-bits but can't have 0.5 or 3 ...
Arseniy's user avatar
  • 2,247
5 votes
1 answer
992 views

What standards cover foot prints for standard part packages?

So far I see some JEDEC standards for part packages, but I need standards for the corresponding footprints. For example MS-026 is a JEDEC standard for a PQFP part, so what would be the standards that ...
Jason's user avatar
  • 302
5 votes
2 answers
3k views

Solderless breadboards: standard size specifications?

Are there standard sizes for solderless breadboards? For example, My teaching project is currently reaching the capacity limit of a 170 pin (17 x 10) breadboard. Is there a standard "next size ...
Mark Harrison's user avatar
5 votes
4 answers
382 views

Industry standard Cat5e cabling

I was wondering about the industry standard for building cabling of Cat5e from the elctrical closet to the end user. More specificly from the patch panel to the wall plate. I was told at some point ...
Chef Flambe's user avatar
  • 1,031
5 votes
1 answer
176 views

How should I select appropriate capacitors to ensure compliance with IEC/EN 61000-4-2:2009 and IEC/EN 61000-4-5:2014 standards for my device?

When applying the IEC/EN 61000-4-2:2009 and IEC/EN 61000-4-5:2014 standards for our device, our consulting firm recommended bypassing the input power jack to the chassis ground using two 33nF ...
Sepehr's user avatar
  • 173
5 votes
2 answers
428 views

How do I find JEDEC registered specifications?

If I'm sharing a circuit for educational purposes, I want to make sure that my parts are common generics. I'd much rather specify "2N3904" than "ON Semiconductor MMBT3904". But not all 2N3904s are ...
Piquan's user avatar
  • 213
5 votes
1 answer
340 views

Is there a metric version of this nomogram?

I found this nomogram, which also appeared in an answer here I think. (larger version here) Is there a metric version of this?
Federico Russo's user avatar
5 votes
1 answer
5k views

Where is the Intel Common Redundant Power Supply (CRPS) Standard Specified?

Intel server reference designs use the Intel Common Redundant Power Supply Standard (CRPS). These documents include a brief over view of CRPS with information like the pin names and refer the reader ...
Pete's user avatar
  • 1,012
5 votes
2 answers
306 views

Is there a common embedded console library

Does anyone know or of use a standard set of source files for a simple embedded console? I've been doing embedded work for a few years now, and I have a set of console code files I have reused in ...
Far McKon's user avatar
  • 151
5 votes
1 answer
188 views

Who sets "standard component" standards?

For example: the LM317. Wikipedia says it was invented by National Semiconductor employees in 1970 — but now if I search for "LM317 datasheet" the results include PDFs from Fairchild Semiconductor, ...
natevw's user avatar
  • 726
4 votes
4 answers
1k views

Are USB 2.0, Type-A, Male-Male cables compliant with USB specification?

This was asked 3 years ago in a similar question but it left out some information to be desired. Are male-male, type-A-typeA usb 2.0 connectors safe, and/or compliant with current standards? Are they ...
BobaJFET's user avatar
  • 1,012
4 votes
4 answers
7k views

uart communication protocol

I'm working on a project where I have to communicate different lengths command from my PC to a microcontroller. (using usb to uart bridge) I already make a litle protocol (start byte, some data, ...
jojo l'abricot's user avatar
4 votes
5 answers
100k views

Australian 3-Phase Colour Code Standard

We're ordering some machinery from China and need it manufactured to Australian electrical standards including the wiring colour code. Unfortunately we don't have any electricians or engineers that ...
Seano's user avatar
  • 163
4 votes
4 answers
1k views

Is the USB B connector still standard?

Nowadays, There are several kinds of USB connectors for USB connection. A type B type micro-B mini-B USB C Etc. The connector sizes are gradually smaller than before. It is a big advantage because ...
Blue Cloud's user avatar
4 votes
6 answers
767 views

Why should any unit be used instead of the watt (W) as a power unit?

I am taking a course on AC circuits and so far I have seen that for the different types of power (read real, reactive and complex) different units are used. For the real power, which is power in fact ...
Severo Raz's user avatar
4 votes
2 answers
10k views

Component naming conventions [duplicate]

Some very common parts have standard acronyms on schematics: resistors are usually named R#, capacitors C#, and integrated circuits U#. Is there a typical standard for these names? If I want my BOM ...
Greg d'Eon's user avatar
  • 3,847

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