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Free PCB coupon via Facebook to 2 random commenters

Posted on Friday, August 18th, 2017 in Free PCBs by DP | 1 Comment

BP

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:

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PRECIsion Power SUpply project

Posted on Friday, August 18th, 2017 in power supply by DP | 1 Comment

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PreciPSU, a high performance power supply project from Mare & Gal Electronics:

PreciPSU is an attempt to build high performance power supply. The idea started few years ago but it was never realised. Some major target performance specs are as follows:

  • three isolated channels
  • around 50W per channel
  • 24V/3A output per channel
  • lowest possible ripple at fastest response
  • small size
  • programmable via USB
  • nice housing with minimalist user interface (2 plugs per channel, knob, button and small display

Read the full post here.

Getting control over a 50 watt CO2 laser cutter from China

Posted on Wednesday, August 16th, 2017 in tools by DP | No Comments

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Unboxing laser cutter Co2 50 watt from China:

There are people around me who think I’m crazy. And they are probably right. Who else would buy a machine from someone he does not know. I have to pay upfront. It is not clear how things will get delivered, what gets delivered, or if it gets delivered at all. Up to the point I can lose the money I have spent. Best of all: that machine is dangerous enough to potentially kill me. And it has the potential to put my home on fire too. Well, that sounds like an exciting weekend project, or not?

See the full post at MCU on Eclipse homepage.

#FreePCB via Twitter to 2 random RTs

Posted on Tuesday, August 15th, 2017 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.

Bus Pirate free PCB build

Posted on Tuesday, August 15th, 2017 in builds, Free PCBs by DP | 1 Comment

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Martin built these free Bus Pirate PCBs. The Bus Pirate is an open source hacker multi-tool that talks to electronic stuff.

If you build a free PCB we’ll send you another one! Blog about it, post a picture on Flicker, whatever – we’ll send you a coupon code for the free PCB drawer.

Get your own handy Bus Pirate for $30, including world-wide shipping. Also available from

Free PCB Sunday: Pick your PCB

Posted on Sunday, August 13th, 2017 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:

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App note: Selecting a FET for use with the Si875x driver

Posted on Sunday, August 13th, 2017 in app notes by DP | No Comments

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Another application note from Silicon Labs on determining the proper FET used on their Si875x driver based on its application. Link here (PDF)

The Si875x enables creating custom solid state relay (SSR) configurations. Supporting customer-selected external FETs, the Si875x combines robust isolation technology with a FET driver to form a complete, isolated, switch. Versatile inputs provide digital CMOS pin control (Si8751) or diode emulation (Si8752) to best suit the application, plus flexible outputs to support driving ac or dc load configurations. A floating secondary side dc voltage source is unnecessary as the product generates its own self contained gate drive output voltage, reducing cost, size, and complexity.

App note: Driving MOSFET and IGBT switches using the Si828x

Posted on Sunday, August 13th, 2017 in app notes by DP | No Comments

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App note from Silicon Labs on their MOSFET and IGBT driver Si828x and how to determining its external components to achieve optimized performance. Link here (PDF)

The Si828x products integrate isolation, gate drivers, fault detection protection, and operational indicators into one package to drive IGBTs and MOSFETs as well as other gated power switch devices. Most Si828x products (except the Si8286) have three separate output pins to provide independent rise and fall time settings and low impedance clamping to suppress Miller voltage spikes. This application note provides guidance for selecting the external components necessary for operation of the driver. Although this application note discusses the topic of driving IGBTs and MOSFETs, users can apply the same concepts for driving other gate-based power switches, such as SiC (Silicon Carbide).

Free PCB coupon via Facebook to 2 random commenters

Posted on Friday, August 11th, 2017 in Free PCBs by DP | No Comments

BP

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:

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A look inside the DS3231 real-time clock

Posted on Thursday, August 10th, 2017 in Chips, reversed by DP | No Comments

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Pete posted an article taking a closer look at Maxim’s DS3231 real-time clock:

Fortunately, Maxim also offers the DS3231, which is advertised as an “Extremely Accurate I2C-Integrated RTC/TCXO/Crystal”. This chip has the 32kHz crystal integrated into the package itself and uses a built-in temperature sensor to periodically measure the temperature of the crystal and, by switching different internal capacitors in and out of the crystal circuit, can precisely adjust its frequency so it remains constant. It’s specified to keep time within 2ppm from 0°C to +40°C, and 3.5ppm from -40°C to +85°C, which means the clock would only drift 63 and 110 seconds per year, respectively. Very cool.

See the full post at HeyPete.com blog.

Teardown and repair of an Agilent 53152A 46GHz microwave frequency counter

Posted on Wednesday, August 9th, 2017 in RF, Teardowns by DP | No Comments

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Agilent 53152A 46GHz frequency counter teardown and repair from The Signal Path:

In this episode Shahriar investigates a faulty Agilent 53152A 46GHz frequency counter. The instrument does not power on and shows no sign of internal voltage presence. Teardown of the instrument reveals a large PCB where all analog and digital circuity is contained. The power supply module is a module components and upon measurements shows no activity.
The power supply is a simple switching architecture with functioning input rectifier and capacitor filter. By using an oscilloscope it is clear that the power supply PWM controller attempts to start. However, the main power supply pin shows unstable voltages indicating inadequate charge retention on the rectifying capacitor. Replacing the capacitor revives the startup condition and the power supply function returns. The PWM controller and main switching transistors are also replaced with new ones. After this repair the unit powers on and passes all self-tests. The unit can successfully measure signal frequencies and power.

More details at The Signal Path.

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

App note: Gate drive characteristics and requirements for HEXFET power MOSFETs

Posted on Sunday, August 6th, 2017 in app notes by DP | 4 Comments

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App note from International Rectifier on driving their Power MOSFETs. Link here (PDF)

The conventional bipolar transistor is a current-driven device. A current must be applied between the base and emitter terminals to produce a flow of current in the collector. The amount of a drive required to produce a given output depends upon the gain, but invariably a current must be made to flow into the base terminal to produce a flow of current in the collector.

The HEXFET®is fundamentally different: it is a voltage-controlled power MOSFET device. A voltage must be applied between the gate and source terminals to produce a flow of current in the drain. The gate is isolated electrically from the source by a layer of silicon dioxide. Theoretically, therefore, no current flows into the gate when a DC voltage is applied to it though in practice there will be an extremely small current, in the order of nanoamperes. With no voltage applied between the gate and source electrodes, the impedance between the drain and source terminals is very high, and only the leakage current flows in the drain.

Free PCB Sunday: Pick your PCB

Posted on Sunday, August 6th, 2017 in Free PCBs by DP | 18 Comments

BP-600x373

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:

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App note: Microcontroller Clock – crystal, resonator, RC Oscillator, or silicon oscillator?

Posted on Sunday, August 6th, 2017 in app notes by DP | No Comments

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App note from Maxim Integrated on clock sources of microcontrollers and their strengths and weaknesses. Link here

The majority of clock sources for microcontrollers can be grouped into two types: those based on mechanical resonant devices, such as crystals and ceramic resonators, and those based on electrical phase-shift circuits such as RC (resistor, capacitor) oscillators. Silicon oscillators are typically a fully integrated version of the RC oscillator with the added benefits of current sources, matched resistors and capacitors, and temperature-compensation circuits for increased stability.

Free PCB coupon via Facebook to 2 random commenters

Posted on Friday, August 4th, 2017 in Free PCBs by DP | No Comments

BP

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…)

TTL triggered stimulus generator

Posted on Thursday, August 3rd, 2017 in AVR, how-to by DP | No Comments

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Scott Harden has a nice build log on his TTL triggered stimulus generator project:

I was presented with a need to rapidly develop a pulse generator to take a TTL input and output a programmable output (for now 0.1 ms pulses at 20 Hz for as long as the input is high). I achieved this with a one-afternoon turnaround and the result looks great! This post documents the design and fabrication of this prototype device, with emphasis placed on design considerations and construction technique.

See the full post at SWHarden.com.

Designing a USB breakout board

Posted on Thursday, August 3rd, 2017 in USB by DP | 7 Comments

USB 2.0 Breakout PCB layout (1)

Alexander Lang has been working on a USB breakout board, he writes:

I often need to intercept USB signals for decoding and measurement purposes. I cut a cable apart last time I needed one but to be honest I much prefer doing things properly. I also noticed that nobody seems to sell a similar product on Ebay, Aliexpress or Amazon! I did find a vendor in the USA on tindie. I also found this product on tindie which is similar but has a current monitoring circuit built in.
Either of these products would work for my purposes but the first product’s shipping costs from the USA seem a little extravagant and I only wanted one or two.
The second product uses pin headers to allow connection which are a bit close together for my liking. It’s often the way of things. When I cannot obtain what I want I make my own!

More details on his blog.

An open source rain and humidity sensor couple

Posted on Wednesday, August 2nd, 2017 in open source, sensors by DP | 2 Comments

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Boris Landoni writes about a new open source rain and humidity sensor project:

It detects humidity through two sensors which are to be used alternatively to let us know when there is water on the ground because it’s raining, or when the water level in a flowerpot is too low and it needs watering.

See the full post and more details on his blog, Open Electronics.

Yet another CXA1191 FM radio receiver

Posted on Monday, July 31st, 2017 in DIY by DP | 2 Comments

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Dilshan Jayakody has published a new build:

This is simple, but very high quality CXA1191S based FM radio receiver system. In this design we use Sony CXA1191S as FM tuner and TDA2003 as an audio amplifier. This receiver system is designed to work with 12V DC power source and it delivers approximately 6W audio output power (with 4Ω speaker load).

Check out more details on his blog here. Project files are available at elect.wikispaces.com.

Free PCB Sunday: Pick your PCB

Posted on Sunday, July 30th, 2017 in Free PCBs by DP | 23 Comments

BP-600x373

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

  • Robert: :)
  • Larry Couvillion: Free PCB Please
  • Chip Stewart: I'd love one of these!
  • zofz: you can switch off the "trimming", see http://cdn.zofzpcb.com/main/Remove.png I hope this will work for you :)
  • Steve: We're gearing up for another busy fall with the student and we love Free PCBs