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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86 views

PCB tracks as wide as possible or just as wide as needed?

what is the best practice regarding the width of PCB tracks? There are of course a few hard constraints : wide enough to keep voltage drop acceptable wide enough to prevent excessive heating at least ...
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1answer
71 views

Absolute Maximum logic voltage best practices

I'm interfacing a PIC24FJ MCU along with a Microchip BM83 BT module. The absolute maximum ratings for the "logic high" level show 3.6 V (with 3.3 V as nominal) on any given I/O port of the ...
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1answer
52 views

Wiring Home Alarm Motion Sensors into a Micro Controller

I have approx. 25 motion detectors designed to be wired into a traditional home alarm system. They take 12V DC and have two built-in switches that open when events occur. One switch opens when motion ...
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1answer
68 views

Best practices for low power consumption (battery operated) I2C pullups

I'm working on a battery powered device and am trying to extend battery life by using a lot of interrupt and timer driven code on the microcontroller (keeping it sleeping most of the time) and putting ...
21
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7answers
4k views

Is it bad practice to parallel power connector contacts?

Say I'm looking for some power connectors for a design, the current requirements are quite high and although I could get a connector with contacts rated for the full current, they're so bulky that ...
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1answer
78 views

What type of wire would be "best practice" for extending stepper motor leads?

I've been using unshielded "communication and security system cable" (https://www.mcmaster.com/8280T32-8280T321/) for running cable to connect stepper motors to motor controllers. I haven't ...
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1answer
84 views

Is it ok to connect only 2 wires of a motor?

I've been recently messing around with motors and found out that I can do everything I need to do (forward, reverse) with just +, - and reversing current. I have some motors that use 3 or 4 wires, and ...
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0answers
56 views

Industrial Oven Control

I'm working on upgrading an ancient oven that we bought second hand, which came with almost zero documentation. I have identified two fans one is exhaust fan and the other is a circulation fan. Is it ...
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3answers
111 views

Single value capacitor or two different in parallel for filtering the power supply for microcontroller

I am trying to design power supply for the STM32F446 for my PCB. I wonder if I should stick to the Datasheet of STM32F446 Page 71 and use two capacitors or be careful about it and maybe just use one ...
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0answers
52 views

Antenna Attenuation, Gain and RSSI calculation

I am using a RAK7258 LoRa gateway operating at EU-868MHz. I am looking to have the gateway and the antenna on each side of a wall (gateway inside, antenna outside) and receive some packets from some ...
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0answers
40 views

Basic shielding practice for simple passive audio project in an enclosure?

I'm a tinkerer but not an electrical engineer. I'm constructing a stereo->mono summing box for my stereo (to listen to Beatles LPs properly, natch). I'm using the design & schematic here for ...
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1answer
87 views

Parallel wires needing to cross - best practices in a schematic? [closed]

I'm sure we've all run in to the following situation: Here, I need to connect pin 1 and 2 on the left to pin 1 and 2 on the right, and vice versa with pin 2. I've considered a few options, however ...
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2answers
247 views

Powering microcontrollers by the circuit it's meant to control [closed]

I often think about controlling things around my house that simply need their power switched on and off (e.g. plant grow lights) on a schedule or via WiFi. I have ESP8266 and ESP32 boards laying ...
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1answer
68 views

Does the cost of an ENIG-finished PCB depend on the surface area of the exposed gold at a large scale?

At very large quantities (>100k-1M), does the cost of an ENIG plated PCB increase as the surface area of the part exposed to gold increases? Intuitively it would make sense, as more gold would be ...
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2answers
139 views

Writing code for new microcontroller/module without examples [closed]

I started learning embedded systems programming(after a long time when I stopped) and I see that most microcontroller boards/modules come with some set of example codes which can be used a base to ...
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0answers
63 views

EAGLE Schematic Design Best Practices

I am currently learning how to use EAGLE. My end-goal is to have a simple PCB printed in China for a project that I am working on. Since I don't have experience in designing schematics, what would be ...
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1answer
62 views

Unused gates on Flip Flops best practices

If I'm using a 74LS112 and I only need to use one flip flop, what are the best practices for the other unused inputs? Should I tie J, K, ~SET, ~PRESET, and CLK on the unused JK FF to Vcc?
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70 views

Are there any generally acceptable UART best practices when it comes to hardware design

Are there any generally acceptable UART best practices when it comes to hardware. Hi, I am trying to design a PCB that uses UART to communicate between two microcontrollers. Are there any generally ...
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0answers
38 views

ADC negative input clipping vs scaling and bias

So, I have this differential ADC (AD7641) and plan to use AD8139 as his driver. The goal is to digitize a signal (a sine wave) of about 3.5Vpp and 36KHz. The signal is actually single-ended and ...
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1answer
142 views

Are Dual Bus Transceiver or Analog Switch best practice to manually switch between SPI devices?

I have two different use cases for 4 lines (this could be an SPI bus or other digital signals). The goal is to manually switch all four lines between the two different use cases with just a single ...
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2answers
251 views

Is there a proper way to enable a digital counter?

I'm asking this because, while learning about how counters work, I read that one can add an input that enables or disables the counter depending on its logical value. Now, my first instinct would have ...
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2answers
269 views

Best practice when choosing a trim pot value

I have a basic comparator circuit I'm working on designing. I want one of the reference voltages to be tunable, so using a trim pot. My Vcc is 12V, so assuming a 1/4 watt pot, 1k seems like the lowest ...
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2answers
206 views

ADC protection best practice

Say you were wanting to measure a signal with a higher voltage than the ADC could handle. Is there some best practice or commonly used circuitry that goes beyond a simple voltage divider to protect ...
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1answer
101 views

Best practice for handling buffers

I'm writing some evaluation code with a lot of rx/tx operations, using the same two buffers and I started to think about how this could easily go very wrong. I can argue that it is nice to clear/...
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2answers
95 views

If you have multiple small pcbs in a single chassis, what is the naming convention for components?

ie, on board 1 do you name resistors R1-R10, then on board 2 name them R1-R10 also? Or do you name resistors R1-R10 on board 1, R11-R20 on board 2, etc? What is the convention or best practice?
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2answers
89 views

What general purpose connectors are used for GPIO data? [closed]

Let's say I have a chassis housing a raspberry pi. I have a second chassis with some neopixels. I want to connect these two chassis with two panel mount connectors and a cable. The cable would be ...
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2answers
84 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 ...
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2answers
2k 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
198 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
207 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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2answers
373 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
8k 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 ...
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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
77 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
1k 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-...
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2answers
688 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
841 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
5k 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
4k 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
5k 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 a ...
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1answer
866 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
3k 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
5k 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
539 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
76 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
567 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 ...
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3answers
218 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
164 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
5k 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 ...