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Capacitor plague? Inside an HP 8620C sweep oscillator and HP 86245A RF plugin

Posted on Wednesday, February 21st, 2018 in Teardowns by DP | 1 Comment

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A teardown of the HP 8620C and HP 86245A by Kerry Wong:

I just picked up an HP 8620C sweep oscillator with an HP 86245A 5.9 GHz to 12.4 GHz RF plugin on eBay. This time around though, the unit does not work. While it was advertised as a working unit I could not get it powered on and there was no sign of life whatsoever. So before I start troubleshooting and repairing the unit, I thought I would do a quick teardown to see what’s inside and if I could spot anything obvious that was out of the ordinary.

More details on his blog here.

Check out the video after the break. (more…)

#FreePCB via Twitter to 2 random RTs

Posted on Tuesday, February 20th, 2018 in Free PCBs by DP | No Comments

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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.

Game audio for the ESP32

Posted on Monday, February 19th, 2018 in library, wireless by DP | No Comments

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ESP32 game audio at Buildlog.Net blog:

I have been working on some games for the ESP32 and needed some decent quality audio with a minimum number of additional components.  I was bouncing between using the DAC and using the I2S bus. The DAC requires less external parts, so I went that way. I ended up creating a very simple library for use in he Arduino IDE. (Note: This only works with ESP32)

Check out the video after the break.

(more…)

Lightronome 1 – The light based metronome

Posted on Monday, February 19th, 2018 in DIY, LEDs by DP | No Comments

Lightronome

Zoltán Gomori documented his lightronome build:

I got a request, to design and build an electronic metronome. You can find several on the market, but the problem it is ether producing voice or the classical mechanical metronome. The requirement here was a visual effect. To be precise four LEDs for 4/4 beat. It is required for drumming where you have no chance to hear the clicking (or maybe just through headphones).

See the full post on PakaHuszar blog.

Check out the video after the break. (more…)

Free PCB Sunday: Pick your PCB

Posted on Sunday, February 18th, 2018 in Free PCBs by DP | 17 Comments

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We go through a lot of prototype PCBs, and end up with lots of extras that we’ll never use. Every Sunday we give away a few PCBs from one of our past or future projects, or a related prototype. Our PCBs are made through Seeed Studio’s Fusion board service. This week two random commenters will get a coupon code for the free PCB drawer tomorrow morning. Pick your own PCB. You get unlimited free PCBs now – finish one and we’ll send you another! Don’t forget there’s free PCBs three times every week:

(more…)

App note: Current limits in electronic fuses using direct and Kelvin R limit connections

Posted on Sunday, February 18th, 2018 in app notes by DP | 1 Comment

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App note from ON Semiconductor about eFuse or Electronic fuse. Link here (PDF)

The primary function of an Electronic Fuse, or eFuse, is to limit current, the same function provided by any fuse or positive temperature coefficient device (PTC). An eFuse, however, provides this function with much more versatility than either of these devices. An eFuse, unlike a standard fuse, need not be replaced after it functions and eFuses also respond more rapidly than a either a fuse or PTC. eFuses can also limit current in situations in which a traditional fuses and PTCs will not work. This is especially true when voltage is first provided to a circuit, such as during a hot plug operation, when inrush current can be extremely high. This application note will explain the basic operation of an eFuse’s current limit function and explain important eFuse concepts such as Overload and Short Circuit currents, and Kelvin versus Direct connection of the eFuse’s current sense resistor.

App note: The four benefits brought by using NCP12600

Posted on Sunday, February 18th, 2018 in app notes by DP | No Comments

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App note discussing extended features of NCP12600, NCP12600 is a multi-mode controller for offline power supplies by ON Semiconductor. Link here (PDF)

Beside the novel multi−mode structure it embarks, the NCP12600 packs a lot of features such as an efficient short−circuit protection architecture, a start−up sequence with a slow switching frequency ramp−up, a fast reset when latched and an auto−recovery scheme when line cycle dropout occurs in latched versions. Let’s discover these novelties in the present application note.

Free PCB coupon via Facebook to 2 random commenters

Posted on Friday, February 16th, 2018 in Free PCBs by DP | No Comments

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Every Friday we give away some extra PCBs via Facebook. This post was announced on Facebook, and on Monday we’ll send coupon codes to two random commenters. The coupon code usually go to Facebook ‘Other’ Messages Folder . More PCBs via Twitter on Tuesday and the blog every Sunday. Don’t forget there’s free PCBs three times every week:

(more…)

Open source 22mm diameter PCB project

Posted on Wednesday, February 14th, 2018 in open source, PCBs by DP | 3 Comments

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An open source 22mm diameter PCB project from Concretedog, that is available on github:

So I posted a while back about how I had used these 22mm pcb’s I’d made in prototyping an ematch ignitor system for use in rocketry. Although I made these stackable boards so they would fit inside a popular size of Estes rocket body tube I’m aware that they are quite useful for lots of things. So i’ve open sourced them so anyone can get some made, or add improve or change them.
There are three boards,an Attiny85 board with some power LED and indicator LED, a SOT89 power supply board which could be built up with either a 3.3v or a 5v supply. Finally there is a “kludge” board which is useful for adding in some thru hole components into the system. Some quick pics here but in the files on Git each board is well documented in a pdf. All the dust components are 0805 so super accessible for hand SMD soldering. :)

See the full post at Concretedog blog.

Repairing the card reader for a 1960s mainframe: cams, relays and a clutch

Posted on Tuesday, February 13th, 2018 in reversed, vintage by DP | No Comments

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Ken Shirriff writes:

I recently helped repair the card reader for the Computer History Museum’s vintage IBM 1401 mainframe. In the process, I learned a lot about the archaic but interesting electromechanical systems used in the card reader. Most of the card reader is mechanical, with belts, gears, and clutches controlling the movement of cards through the mechanism. The reader has a small amount of logic, but instead of transistorized circuits, the logic is implemented with electromechanical relays.1 Timing signals are generated by spinning electromechanical cams that generate pulses at the proper rotation angles. This post explains how these different pieces work together, and how a subtle timing problem caused the card reader to fail.

See the full post on his blog.

#FreePCB via Twitter to 2 random RTs

Posted on Tuesday, February 13th, 2018 in Free PCBs by DP | No Comments

IRToy-600x369

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.

Retropie plug in USB speaker

Posted on Monday, February 12th, 2018 in R-Pi by DP | No Comments

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A detailed instructions of how to make this DIY retropie plug in usb speaker from Facelesstech:

The 2 down sides to my ZeroBoy build I did recently were that it didn’t have a build in battery power and that it didn’t have sound. I seen that the MintyPi was using a USB sound card to give their handheld a speaker by soldering a speaker to the 3.5mm jack. So I thought I could do the same to add sound to my ZeroBoy.

Check out the video after the break. (more…)

Free PCB Sunday: Pick your PCB

Posted on Sunday, February 11th, 2018 in Free PCBs by DP | 19 Comments

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We go through a lot of prototype PCBs, and end up with lots of extras that we’ll never use. Every Sunday we give away a few PCBs from one of our past or future projects, or a related prototype. Our PCBs are made through Seeed Studio’s Fusion board service. This week two random commenters will get a coupon code for the free PCB drawer tomorrow morning. Pick your own PCB. You get unlimited free PCBs now – finish one and we’ll send you another! Don’t forget there’s free PCBs three times every week:

(more…)

App note: LEDs – The future of horticultural lighting

Posted on Sunday, February 11th, 2018 in app notes by DP | 1 Comment

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LEDs used in a controlled environment greenhouse farms, an app note from Würth Elektronik. Link here (PDF)

Greenhouse farms may not be a new technology but with an every growing world population and the move towards sustainability, intensive yet highly efficient and standardized food production will increasingly become the norm in future years opening a potentially huge new agricultural sector that incorporates the latest technologies from the bioscience and engineering fields. But how can researchers and personnel from these separate fields understand the mutually dependent requirements of indoor greenhouses? Photosynthesis is the process that converts water and carbon dioxide into complex carbohydrates (i.e. sugars) and oxygen using energy from light. However, although the energy radiated by the sun that reaches the earth’s surface consists of the entire spectrum of visible light (and more), plants only utilize specific frequencies of light for photosynthesis. These frequencies are related to the absorption characteristics of different pigments that are present within organelles called chloroplasts that are responsible for different functions of photosynthesis.

Light emitting diodes are solid-state, light generating components that, have become and will continue to be one of the greatest drivers in the expansion of internal greenhouses due to their advantages over incandescent bulbs, fluorescent bulbs, high-pressure sodium lamps and mercury lamps. Their main advantage stems from their ability to generate specific wavelengths of light. To meet the requirements for Horticultural LED’s for Indoor-farming, Würth Elektronik offers the WL-SMDC SMD Mono-color Ceramic LED Waterclear series of LEDs. The WL-SMDC range has been expanded to include wavelengths of 450 nm (Deep Blue), 660 nm (Hyper Red) and 730 nm (Far Red), which have been selected to match the absorption spectra of photosynthetic pigments. In addition to the existing products in the range, a diverse range of combinations is possible that can be catered to the target cultivar.

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

Posted on Sunday, February 11th, 2018 in app notes by DP | No Comments

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Application note form Würth Elektronik about EM radiation radiated from inductors in DC-DC converters. Link here (PDF)

This Application Note focuses on the Electro-Magnetic (EM) radiation behavior of power inductor(s) in DC-DC converters, which is dependent on several parameters such as ripple current, switching frequency, rise & fall time of a switching device, the core material and its permeability and suggests several design tips to mitigate these EMI effects.

Optimizing the 5v to 170v Nixie tube power supply design (part 2)

Posted on Friday, February 9th, 2018 in power supply by DP | No Comments

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Mark Smith has a nice write-up on optimizing the 5v to 170v Nixie tube power supply:

Since this power supply is just a fun design for an upcoming Nixie tube clock project of mine, I have the time to achieve ESE. While in Part 1 I described the equations and simulations, in this Part 2, I collected experimental results to complete the design. In the process of finalizing the design, I was able to discover a couple of key design improvements and I’ll share these changes with you. The updated schematic, BOM, Kicad Layout, and design files are located at Github.

Via surfncircuits.

STM32F103 vs GD32F103 round 2: Blink a LED

Posted on Wednesday, February 7th, 2018 in ARM, LEDs by DP | No Comments

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A follow-up to the STM32F103 vs GD32F103 round 1- Solderability post, Sjaak writes:

The defacto ‘hello world’ for microcontrollers is blink a LED at a steady rate. This is exactly what I’m going to do today. I made a small 5×5 development board, soldered it up and started programming. In this first example we not gonna use fancy IRQs or timers to blink at a steady rate, but we insert NOPsas delay. This would give an idea of the RAW performance of the chip. The used code is simple; set up the maximum available clock available and then toggle RA0 for ever.

More details at smdprutser.nl.

#FreePCB via Twitter to 2 random RTs

Posted on Tuesday, February 6th, 2018 in Free PCBs by DP | No Comments

IRToy-600x369

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.

Teardown of an HP 8671A microwave frequency synthesizer

Posted on Monday, February 5th, 2018 in Teardowns by DP | No Comments

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Kerry Wong did a teardown of an HP 8671A microwave frequency synthesizer:

I recently bought an HP 8671A microwave frequency synthesizer on eBay. This synthesizer can generate signals from 2GHz to 6.2GHz with an unleveled output of more than 8dBm. It is a nice complement to my HP 8642B signal generator and Wavetek 907 signal generator. Using these generators, I can now generate signals of pretty much any frequencies under the 12GHz range. A video of this teardown is linked towards the end of this post.

More details on his blog here.

Check out the video after the break. (more…)

Free PCB Sunday: Pick your PCB

Posted on Sunday, February 4th, 2018 in Free PCBs by DP | 12 Comments

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We go through a lot of prototype PCBs, and end up with lots of extras that we’ll never use. Every Sunday we give away a few PCBs from one of our past or future projects, or a related prototype. Our PCBs are made through Seeed Studio’s Fusion board service. This week two random commenters will get a coupon code for the free PCB drawer tomorrow morning. Pick your own PCB. You get unlimited free PCBs now – finish one and we’ll send you another! Don’t forget there’s free PCBs three times every week:

(more…)

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Recent Comments

  • KH: I think no plague. Both failed capacitors are on the same side. Look at the backplane, it's likely the failed caps were on the left...
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