App note: The behavior of electro-magnetic radiation of power inductors in power management

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Würth Elektronik app note on EM radiation emission from power inductors. Link here (PDF)

DC-DC converters are widely used in power management applications and the inductor is one of the key components. The usual focus is on electrical performance characteristics such as RDC, RAC and core losses. But, the electro-magnetic radiation characteristics can often be overlooked.

Due to the switching action in SMPS, AC voltage/current is produced over the inductor. Since, an inductor can, in effect, operate as a transmitting loop antenna, the electromagnetic radiation depends on a number of factors. These include the source properties such as core material, shielding material and the orientation of the start of the winding amongst others.

Electromagnetic radiation of an inductor in the low frequency spectrum range (100 kHz to 30 MHz), which is caused by the switching frequency and harmonics, is dependent on whether the inductor is shielded and the winding properties. Whereas, in the high frequency spectrum range (30 MHz to 1 GHz), where emissions are caused by ringing frequencies and their harmonics, the electromagnetic radiation is more dependent on the shielding characteristics of the core material, switching frequency and transitions of the switching converter.

from Dangerous Prototypes http://bit.ly/2X9Ru3t

App note: How to use power inductors

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A great guide from TDK about power inductors used in DC-DC converters. Link here

As electronic devices become more advanced, the power supply voltage of LSIs used in them is lowered, so their power consumption can be reduced and their speed increased. However, a decrease in the power supply voltage also causes the requirements regarding voltage fluctuations to become more severe, creating a need for high-performance DC-DC converters to fulfill these characteristic requirements, and power inductors are important components that greatly affect their performance.

from Dangerous Prototypes http://bit.ly/2P98yUx

DIY 3D printer project

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Frank documented a 3D printer build, called Hephaestus:

I finally did it, I designed and built my own 3D printer. This is in no way “the best 3D printer”. Instead, this was an epic and nightmare project that exercised my ability to engineer and build my own CNC machine. Along the way, I figured out what I did well and what I did badly, mistakes were made and sometimes fixed, even ignored.

You can find the build log on Eleccelerator project page.

from Dangerous Prototypes http://bit.ly/2P4EMA2

RetroZero (retropie handheld)

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Facelesstech published a new build:

I’ve been on a quest for while now trying to build a retropie handheld that was functional but didn’t break the bank. So far I’ve made ZeroBoy – A poor man’s retropie “portable” and a follow-up ZeroBoy rev C – An improved poor mans retropie portable. These were great but I think I have made a much better system with all the features included.

More details  on Facelesstech blog.

Check out the video after the break.

from Dangerous Prototypes http://bit.ly/2KkkKTq

App note: Operating voltage ratings for inductors

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Coilcraft’s app note on why inductor’s voltage ratings are uncommonly mentioned in most applications. Link here (PDF)

Voltage ratings are often specified for many electronic components, including capacitors, resistors and integrated circuits, but traditionally this has been rare for inductors. Recent trends, particularly the introduction of higher voltage rated semiconductor devices, have created a new emphasis on operating voltage as part of the inductor selection process. Inductors once considered optimized for high current, low voltage applications are finding homes in new designs that apply higher voltage stress to the inductor.

from Dangerous Prototypes http://bit.ly/2I3IzNr

App note: Power supply topologies – Forward of Flyback? Which is Better? Both!

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App note from Coilcraft camparing two recognized power supply topologies. Link here (PDF)

Beatles or Stones? Michael or LeBron? Deep dish or thin crust? Forward or flyback? These are just a few of the age-old questions that have been hotly debated over the years, people arguing their opinions with great vigor. But, the truth is, most of the time the answer is both, due to the merits of each.

In this article, we will focus on forward or flyback. We’ll discuss the characteristics of active clamp forward and continuous conduction flyback isolated power supply topologies and demonstrate the design and performance trade-offs of each using two telecom-oriented power supplies as examples.

from Dangerous Prototypes http://bit.ly/2uScfV6

HX711 load cell amplifier library for AVR ATmega

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A HX711 load cell library for AVR ATmega:

HX711 is a precision 24bit ADC IC designed for weigh scales and industrial control applications to interface directly with a bridge sensor.
A load cell is a transducer that is used to create an electrical signal whose magnitude is directly proportional to the force being measured.
The library you can find here is usefull to implement a weigh scale using the HX711.

More details on Davide Gironi’s blog.

Check out the video after the break.

from Dangerous Prototypes http://bit.ly/2FXaz1V

#FreePCB via Twitter to 2 random RTs

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Every Tuesday we give away two coupons for the free PCB drawer via Twitter. This post was announced on Twitter, and in 24 hours we’ll send coupon codes to two random retweeters. Don’t forget there’s free PCBs three times a every week:

  • Hate Twitter and Facebook? Free PCB Sunday is the classic PCB giveaway. Catch it every Sunday, right here on the blog
  • Tweet-a-PCB Tuesday. Follow us and get boards in 144 characters or less
  • Facebook PCB Friday. Free PCBs will be your friend for the weekend

Some stuff:

  • Yes, we’ll mail it anywhere in the world!
  • Check out how we mail PCBs worldwide video.
  • We’ll contact you via Twitter with a coupon code for the PCB drawer.
  • Limit one PCB per address per month please.
  • Like everything else on this site, PCBs are offered without warranty.

We try to stagger free PCB posts so every time zone has a chance to participate, but the best way to see it first is to subscribe to the RSS feed, follow us on Twitter, or like us on Facebook.

from Dangerous Prototypes https://ift.tt/2K02EGs

Qi wireless power receiver from scratch

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Vinod made a Qi wireless power receiver using Attiny13, that is available on GitHub:

I have only two aims while trying this. The receiver should get powered by the transmitter continuously. I should be able to control the power received by adjusting the error packets, in my case I am trying to keep received voltage always 10v.
There are lot more but I am only interested in this two features for now, so I will not be following the complete Qi specs described on the WPC documents, by the way, it worked for me without any issue. This is purely experimental.

See the full post on his blog.

Check out the video after the break.

from Dangerous Prototypes https://ift.tt/2YJKPyz