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Questions tagged [best-practice]

A best practice is a method or technique that has consistently shown results superior to those achieved with other means, and that is used as a benchmark

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2answers
66 views

Higher precision with less digits?

Consider an ideal digital milliammeter (zero resistance, zero uncertainty on AD converter input) with realistic (noisy, hysteresic, etc.) AD converter output and a \$3½\$ -digit display. Often when we ...
8
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2answers
182 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 ...
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2answers
5k views

Is it ok to 'snake' the flow of my schematic?

I recently watched this video by EEVblog on drawing schematics. One thing he talked extensively about was that the logical flow of a schematic should flow from left to right. Whilst this makes ...
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2answers
61 views

Passive Component ratings displayed on schematic - Use actual value or design requirement value?

When placing a passive component such as a cap or resistor on schematic, most people usually place the relevant rating (usually power for resistors, voltage for caps, and current for inductors) next ...
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1answer
116 views

5V Tolerant Way To Generate Rising Edge Signal on USB Connection

I have a microcontroller device that can be awakened from deep sleep mode when it detects a rising edge signal on a wakeup pin. The wakeup pin is 5V tolerant and I'd like a connection to a USB port to ...
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1answer
107 views

Parallel busbars: how to orient?

As part of my research, I'm doing calculations on a hypothetical high-current (4000 A) medium-voltage (5000 V) DC power transmission system using two parallel busbars. However, I need to decide how ...
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3answers
4k views

What is the smallest metal object you can ground yourself with?

Say I am installing a new CPU in my desktop motherboard and I am interested in grounding myself (by touch or one of those nifty bracelets) to avoid damaging my components. What is the nature of ...
13
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5answers
2k views

SMD IC mounted upside-down inside a drill hole for extreme low-profile requirements

I don't know if the title is descriptive enough, but I came across this PCB and could stop to wonder about its brilliant design. It is an aftermarket trigger controller for an airsoft gun that works ...
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1answer
56 views

High voltage loads best practice [closed]

I am on a learning curve to gain updated knowledge of 1.5 kV MOSFETs and IGBTs and their drivers, flyback transformers and the many ways of generating and switching high voltages. My question is what ...
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1answer
360 views

Is it bad to short a DC motor for a long time?

I am using one of those small yellow "robot" DC motor like this one, on a circuit where the motor will turn on a couple of times under certain circumstances. I am thinking of designing a normally-...
4
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2answers
406 views

Power and Ground planes The Henry Ott way or split ground planes

Seeing a lot of mixed infomation around involving ground planes on multilayer boards. For a mixed signal mulitlayer PCB which is the preferred method? I know every board is different and it depends ...
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3answers
294 views

Do I need to solder every header pin to the board?

When soldering MCU (Arduino and like) to perforated board I apply solder only to the pins in use, leaving the unused ones just sitting in the hole. I do this to minimize soldering accidents. The ...
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2answers
2k views

IC power pin connection for noise immunity and decoupling

There's been much talk on other Q&A threads on how to connect decoupling capacitors to an IC, resulting in two completely opposite approaches to the problem: (a) Place decoupling capacitors as ...
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6answers
3k views

Are there any standard patterns for wiring a breadboard/solderboard? [closed]

My breadboard wiring is disorganized and this makes complex circuits hard to debug and so on. Are there any standard rules for how to arrange the wiring? Something like "always leave x holes between ...
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4answers
2k views

Antiresonance of multiple parallel decoupling capacitors: use same value or multiple values?

My quesiton: Is it better practice to put same-valued capacitors in parallel of capacitors of different values to decouple the high-frequency noise caused by digital ICs? Background Digital IC need ...
0
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1answer
357 views

Op-amp variable reference voltage

Is it appropriate to trim signal offset to an op-amp using only a divider and a trim-pot? For stable operation would it be preferable to connect drive the potentiometer from precision references or ...
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5answers
2k views

Why put unpopulated components on a BOM?

I've ran into quite a few engineers from unrelated backgrounds that put unpopulated components on the BOM. Some will do a section clearly labelled DNP at the bottom, others will leave them dispersed ...
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3answers
1k views

How to measure Inductor maximum current?

I have an inductor and seller claims that inductor supports a maximum of 5A current and he asked me to test it myself. Can someone help how to test that how much this inductor can support/ draw ...
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1answer
351 views

Bypass capacitor before or after circuit, does it matter?

My colleague claims it is best practice to put a bypass capacitor "before the circuit" on the PCB, and even complicates the PCB design in order to ensure this rule is followed. I claim it doesn't ...
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0answers
70 views

I've gotten an oscilloscope! How do I take care of it? [duplicate]

I'm happy to say that I've gotten my first ever oscilloscope!! I want to make sure that I take good care of this equipment. But I'm afraid that while I'm new to oscilloscopes, I'm new to taking care ...
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1answer
307 views

Microcontrollers - disconnect I2C and Serial lines after loading from EEPROM

I am using a P8X32A (Parallax "Propeller" microcontroller) in many of my hobby projects. It has no NV RAM internally on the chip so it loads its program code from either a serial port TX/RX pins or ...
0
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3answers
177 views

Is it good general practice to avoid powering components from the 5v pin on an arduino?

Most examples and tutorials have you power small components by connecting them to the 5v pin on the Arduino. As part of my learning process, I've messed up an arduino or two by not considering the ...
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1answer
159 views

Need for 3.3V regulator

I have seen several products ( such as the pitft for the raspberry pi, and most other small tft screens) which use a 3.3V regulator on the 5V power rail to provide power to the 3.3V system. In some of ...
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4answers
3k views

Ground plane directly underneath physically large 100 µH inductor?

I plan to use a physically large ferrite core inductor (Murata part "1410478C", 100 µH at 1 kHz) in a 12 V, 7 A DC filter circuit. It will be mounted on topside of a four-layer PCB ...
4
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1answer
383 views

Does a very small via reduce the drawbacks of a non-filled via-in-pad?

I have been doing a lot of vias in pads on my 2 layer prototypes (which I hand-solder) because I save a lot of space and the end result looks very compact and neat. However, I have been researching ...
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4answers
2k views

Why were hatched polygons pours used instead of solid pours in the past?

While reading [David L. Jones]'s PCB Design Tutorial, he mentions that hatched polygon pours are a thing of the past. Solid fills are preferred, hatched fills are basically a thing of the past. (...
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1answer
1k views

How does trace/via clearance affect parasitic inductance if they go to the same net

After reading [Mike DeSimone]'s response regarding good decoupling and bypassing practices I kept wondering about distance between wires (wire = trace or net) . [Mike DeSimone] comments that wires ...
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0answers
227 views

Is this a 'proper' way to represent a circuit schematic? [duplicate]

Is this a reasonable way to do a wiring diagramme. What are the common practices when making this sort of thing? Basically I am a compleat beginner and would love to know if this is a proper neat way ...
9
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3answers
777 views

SPI bus connections - to loop or not to loop?

I have a question regarding the physical connection of an SPI bus. I have an SPI master (a PIC32 device) and a number of slaves (in this case PIC16 devices). I'm only writing to the slaves, and the ...
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4answers
2k views

Coin cell battery retainer, problems and best practices

I use Memory Protection Devices BK-913 CR2032 Through hole battery retainer. I use Adafruit's CR2032 PCB footprint, which is almost identical to the recommended footprint in the datasheet for the ...
6
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2answers
3k views

Serial Number Generation

I am working on a product that will need a unique serial number for each device. Are there any "recommended practices" for serial number generation? Since I never saw a device with serial number 1, ...
18
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2answers
1k views

Should all traps always be defined?

I've seen two cases now with dsPIC 30F4013 where the controller was resetting due to an undefined trap. Why these traps were getting raised in the first place is still a mystery, but that's not my ...
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4answers
13k views

Why is designed active low?

I buy a 2 channel relay module for Arduino. I surprised that why this relay module is designed active low? Circuit: i means that when we connect In1 to low V (GND) relay turn on. Is there any reason ...
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1answer
4k views

Using a human finger to test a circuit

In this Linear Tech App Note 13, page 28, Jim describes: A final form of probe is the human finger. Probing the circuit with a finger can accentuate desired or undesired effects, giving clues ...
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7answers
3k views

Is circuit design based on min/max values good practice?

Time and again I am arguing with a colleague of mine about the question above. When I design a circuit for mass production (> 10k/a) I want to make it robust against every possible variation of ...
2
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1answer
92 views

Is there a convention for lines separating areas in circuit diagrams?

I often see boxes of various styles to separate areas and increase clarity in circuit diagrams. I'm wondering if there is a line style convention in circuit diagrams for illustrating: A set of parts ...
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2answers
176 views

Best practice for probing capacitance sensitive test point in a switching supply?

I need to probe the hot side of a switching supply between the drive transistor and inductor (Marked TP on diagram). I tie my scope ground to the device ground with short fat wire and when probing ...
0
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1answer
151 views

Should you always band limit a signal into an opamp when you are trying to control noise - even at DC?

Saw a Youtube video from TI talk about opamp noise and one of the points they made was limit your bandwidth. TI:How to select an op amp based on datasheet noise specs While I do understand the ...
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0answers
469 views

How to learn circuit design if I already know some circuit theory [closed]

I'm a recently graduated electrical engineer, but my curriculum never focused on electronics, besides the standard introductory level courses. I specialized in telecommunications and I mostly work on ...
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2answers
3k views

What lead-free solder type is convenient to use for hand-soldering?

I have read some discussions about the lead-free solders on the forum, but could not see what solder type is easier to use for hand soldering (among lead-free ones)? As an example, I see only two ...
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3answers
995 views

Setting up a non-ESD area in a lab

this question is regarding standards and/or best practice guidelines for ESD control in a professional lab environment. We are currently tightening up our (admittedly too lax) ESD control in the labs,...
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2answers
720 views

Is it wise to use an Arduino to power a crystal oscillator?

I'm building a small VGM audio player. I currently have a SN76489 (here) that is clocked from a 3.579 crystal oscillator. When ...
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3answers
2k views

Reading a multibyte volatile variable that is updated in an ISR

Consider the Arduino code at the end of this post for full reference that makes LED13 blink in a 0.5Hz rhythm driven by timers. It is just a proof of concept, I know it can be improved for various ...
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3answers
63 views

Is the battery being drained?

I'm building a simple intrusion alarm system with a piezo buzzer fed by a 9V battery, I have a switch to activate/deactivate the alarm, and a trigger (like a switch) connected to a tripwire so if ...
0
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4answers
2k views

How would I protect my hardware from unwanted magnetic induction?

To my understanding, magnetic induction is the process of varying magnetic fields producing a potential difference in a conductor, resulting in current. How would I protect my hardware from strong, ...
2
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1answer
839 views

Cleaning oscilloscope range switches

The various range switches on my oscilloscope obviously collected some dirt over the years. Sometimes the input attenuators show a frequency dependent response (just like poorly matched probe) and the ...
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3answers
200 views

My fans are not marked with a withstand voltage between the circuit and the plastic case; what is best practice?

I'm designing a new series of products in metal chassis containing plastic fans. The fans' power supply is referenced to the negative DC rail of a variable-frequency drive, and the fans are mounted to ...
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1answer
423 views

prevent metavalues for input ports in VHDL simulation

In my VHDL design I have entities with port definitions similar to this: ...
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1answer
368 views

“Proper” way to wire an unbalanced TRS-to-TRS cable

I was about to wire up a short 3.5mm TRS lead when I realised that I actually don't know how -- at least, I don't fully remember a non-conflicting set of best practices. This is the standard stereo ...
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1answer
4k views

VHDL impure keyword

I have vhdl code along these lines (explanation below): ...