Keysight MXA revision-b signal analyzer / Spectrum analyzer review, analysis & experiments


Keysight MXA revision-b signal analyzer / Spectrum analyzer review, analysis & experiments from The Signal Path:

In this episode Shahriar reviews the long awaited Keysight MXA Signal Analyzer (N9020B). The new X-Series Spectrum Analyzers from Keysight offer an entirely re-designed GUI interface which supports multiple tabs as well as multi-touch interaction.

Check out the video after the break.


Teardown and analysis of microwave (26.5GHz) electro-mechanical step attenuators

Teardown and analysis of microwave (26.5GHz) electro-mechanical step attenuators from The Signal Path:

In this short episode Shahriar takes a close look at a pair of Hewlett Packard microwave electro-mechanical step attenuators operating up to 26.5GHz. Mechanical attenuators offer excellent repeatability, low insertion loss and nearly limitless linearity. The teardown reveals that the construction of both modules is very similar on the microwave path. In fact, the lower-frequency model still uses the same attenuator components. The newer model employs electronic control circuity while the older generation attenuator uses purely mechanically controlled DC path. Both models use a solenoid style actuators for step attenuation control.

4-20ma panel meter teardown


Teardown of a 4-20ma panel meter from SteelCity Electronics:

Below is a panel meter that has been used in some sort of industrial process. It was manufactured in 1980 and I’m not quite sure who the manufacturer was – the company’s logo is not easy to read but it might say, “Aumano”. What caught my attention with it was that it includes high and low needles as well as indicators and relay outputs for the high and low limits.

More info at SteelCity Electronics homepage.

Teardown, experiments and calibration of an Ist-Rees laser spectrum analyzer


Ist-Rees laser spectrum analyzer teardown from The Signal Path:

In this short episode Shahriar takes a close look at an Ist-Rees laser spectrum analyzer. This simple instrument is based on a continuously rotating diffraction mirror to detect various wavelengths. A trigger signal is used to denote the beginning of the scan and the front-panel display shows the current selected wavelength. By aligning the output signal with the trigger signal the wavelength of the input light can be measured.
After the unit teardown, the instrument is used to measure the wavelength of a semiconductor 1310nm laser. The unit is calibrated using this source and is then used to measure the infrared leakage wavelength from a green laser pointer.

Check out the video after the break.

Tear down of a super capacitor

A teardown video of a 1 Farad super capacitor from Electronupdate:

In a recent video on the tear down of an electrolytic cap a viewer was wondering what a super capacitor looks like.
They have much more capacitance: 10,000 time more on average for the same volume.
Surely this means the physical construction must be amazing! Interestingly enough, the construction is almost identical.. the secret is in the dielectric.

More details at Electronupdate blog.

Curtis 1231C-8601 500A PWM DC motor controller teardown


Jay did a teardown of a Curtis 1231C-8601 500A PWM DC motor controller:

The Curtis 1231c-8601 power board is relatively simple. It uses 18 MOSFETS in parallel to switch current from the motor- terminal back to the battery- terminal (the motor+ lead is already connected to battery+). The MOSFETs it uses are IXYS IXTH50N20 SP9536 chips. The center lead is bent up over the chip and soldered to a ring terminal, such that the screw that attaches the chip to the heat sink also electrically connects that pin to the heat sink.  Most chips that attach to a heatsink have a metal back, but the IXTH50N20’s used here do not, so it appears that they had to take extra assembly steps to electrically couple it to the heatsink.

More details at Jay’s blog.

Solar battery charge controller teardown

A teardown video of a solar battery charge controller from Electronupdate:

A solar battery charger: one side goes to a Solar Panel, the other to a lead-acid battery. A charge controller allows the battery to be safely charged.
Snagged off of Amazon. Seemed really cheap at $17.36.
A look at the assembly quality tells me why. Bad soldering, mechanical errors, wrong wire sizes….
What is baffling, however, is that many of these workmanship issues (beyond the missing “fuse”) are just due to lack of attention… i.e. it would cost no more to do it right.

More info at Electronupdate blog.

Books You Should Read: The Hardware Hacker

There’s no one quite like Andrew ‘Bunnie’ Huang. His unofficial resume begins with an EE degree from MIT, the author of Hacking the Xbox, creator of the Chumby, developer of the Novena, the first Open Source laptop, and has mentored thousands of people with dozens of essays from his blog.

Above all, Bunnie is a bridge across worlds. He has spent the last decade plying the markets of Shenzhen, working with Chinese manufacturers, and writing about his experiences of taking an idea and turning it into a product with the help of Chinese partners. In short, there is no person better suited to tell the story of how Shenzhen works, what can be done, and how to do it.

Bunnie’s The Hardware Hacker ($29.95, No Starch Press) is the dead tree expression of years of living and working in Shenzhen, taking multiple products to market, and exploring the philosophy that turned a fishing village into a city that produces the world’s electronic baubles.

This is not Bunnie’s first book on Shenzhen. Earlier this year, The Essential Guide to Electronics in Shenzhen was released through CrowdSupply, and it’s the perfect book to keep on your carry on for your flight to Hong Kong. It’s a phrase book, designed to help non-Mandarin speakers get off the plane, find a bathroom, buy a SIM card, tell a taxi to drive to the border, and find a reel of 4.7 uF SMD electrolytic capacitors at the sprawling Hua Qiang Bei markets.

view-of-hqb-shenzhen-lychee-parkThe Essential Guide to Electronics in Shenzhen is something you want to read before heading to the Chinese consulate to get your visa, and it’s a mandatory item for your carry on, but it’s book-ness is questionable. It’s a guide, really. You’ll be able to find your hotel and a bathroom with The Essential Guide, but you won’t be able to make sense of anything. The Essential Guide doesn’t tell you the sellers in the electronic market stall can turn a 2 GB SD card into one that reports 16 GB of storage with the press of a button. This book doesn’t tell you Open Source doesn’t mean what you think it means. There isn’t a single word on what Design for Manufacture actually means.

Consider The Hardware Hacker the prerequisite for stuffing The Essential Guide into your luggage. Instead of a survival guide, The Hardware Hacker will tell you how to succeed at whatever endeavor brought you to Shenzhen in the first place. It is, at its core, the primer for understanding the culture of making something in China, how to build thousands of things, and why Open Hardware works.

The Shanzhai and Gongkai

The West has a few ideas about Open Source that basically boil down to, ‘everything must be open source’ or ‘everything should be open source’. The former ideology results in GPL, whereas the latter results in the more permissive licenses. Either way, these licenses are derived from a hack of sorts on copyright. The creator of a piece of software, a painting, or a ship hull has an automatic, exclusive rights over the work’s use and distribution. These rights include the right to give the work away, and to give the work away under conditions. All of this is fairly well codified in the legal system, and even though a lot of the thought that has gone into the last few decades of Open Source hasn’t been tested in the courts, it at least makes sense. China does not have anything resembling copyleft; for that, you would need some semblance of copyright.

fernvale-gongkai-phone-thumbIn China, Open Source is gongkai. It’s a system of Open Source that is completely unlike anything seen in the West. That’s not to say arguments for and against BSD don’t happen in Mandarin; that’s another word, though. For English speakers, the literal translation of Open Source (in capital letters) is kaiyuan. From what Bunnie writes, including a license with your source in China is rare.

Gongkai isn’t so much a license or philosophy, but a way of doing business through sharing. Under this system, if you were to create a design, you would simply give the blueprints away, making sure to add your name and phone number in the corner. Blueprints are traded, improved upon, and constantly remade. The result is a complete lack of version control, but an absolutely democratic system of technological improvement.

This system of open source (lowercase) has led to the rise of the shanzhai, the term for underground or unaffiliated engineers. These shanzhai are the people responsible for Ferrari-shaped cell phones, the infamous $12 cell phone, and bizarre products whose feature set is a word soup. Put some shanzhai in a factory, and they’ll iterate over hundreds of designs, creating smart watches years before the Apple Watch.


Bunnie is, after all, an expert in the culture of Chinese manufacturing. The stories from The Hardware Hacker wouldn’t be out of place in any Western factory or distributor. Yes, you will find people selling reprogrammed and relabeled SD cards, and you will find counterfeit handbags made on a ghost shift. These are aberrations, or at least that’s the impression I got from The Hardware Hacker.


Earlier this year, we took a look at another book on Chinese manufacturing culture, Poorly Made In Chinaand the impression the author gives could not be more different from Bunnie’s description of Shenzhen.

The backdrop of Poorly Made is the author, Paul Midler, acting as middleman between a cosmetics tycoon in Jersey and a shampoo factory somewhere in China. Where Bunnie tells us that a factory needs to get paid, and they’ll only get paid by delivering what they promise, Midler’s China could not be more different. Stories of the manufacturer bottling mint shampoo when a floral scent was ordered were par for the course, thanks to the mint fragrance being a few cents cheaper. Midler’s factories were dirty, and the only way to get the upper hand in a negotiation was to out-scheme the other party.

Bunnie’s China is nothing like this. Yes, you’ll find schemers and shysters, but you’ll find those in New York, London, and Berlin, too. Taken as a whole, Bunnie tells us there’s nothing inherently unscrupulous about manufacturing in China.

Which of these realities is closer to the truth is open to debate. There would obviously be a difference in an electronics manufacturer in Shenzhen and a factory that produces shampoo a few hours outside the city.  I think, though, Bunnie may have a better grasp here; contract work requires a contract, after all, and no one gets paid until the work is done. A years-long relationship with a shampoo manufacturer is something I don’t expect the Hackaday reader will ever experience. Building an electronic gizmo in Shenzhen, perhaps. If you’re looking for a look at the manufacturing culture of China, Bunnie’s might be the best.


What does The Hardware Hacker bring to the table? The first third of the book is an excellent introduction to building more than one thing. Design for manufacture, testing, cost of goods sold, and everything else you’re required to know before building selling the product you’re working on are covered well in this book. Of course, no book on the business of making things could ever be considered complete. The Hardware Hacker is, however, a great introduction.

hardware_hackerAnyone reading The Hardware Hacker is going to get a very good idea of how to make things. Whether that’s a completely Open Source laptop, dealing with fake SD cards, or managing a supply chain, The Hardware Hacker takes the reader from knowing nothing to at least knowing what they don’t know.

Limiting my assessment of this book does it a disservice – the real value here is Bunnie’s take on the culture of Chinese manufacturing. The shining light of this book is Bunnie’s take on how Open Source works in China, how it’s not really Open Source in capital letters, and how the words ‘sharing economy’ have vastly different meanings on either side of the Pacific.

Over the last decade, Bunnie has cemented his position as a bridge between worlds. On one hand, you have an MIT graduate, familiar with signing NDAs and rightfully frustrated by having to pick up a phone to get a price for a component. On the other hand, you have someone who has deftly maneuvered around Shenzhen, managed supply chains, and actually gets why Shenzhen is the manufacturing capital of the world. Bunnie is expert in bridging these two worlds, and for that knowledge alone The Hardware Hacker is worth the price of admission.

Filed under: Featured, Interest, reviews

Teardown of a Vivitar Rapid battery charger


Kerry Wong did a teardown of a Vivitar rapid battery charger for the NP-FW50 lithium-ion battery pack used in Sony A6000 digital camera:

The circuit board itself though looks surprisingly clean and well designed. It does not use any dedicated lithium ion battery charging ICs however. Rather a MC34063A buck/boost DC-DC converter chip is used to provide the current limited 8.4V constant voltage. This arrangement is less ideal then the typical lithium ion battery charging technique. Typically, the charging current is held constant until the voltage reaches a certain threshold and then the charger switches to constant voltage mode. Once the charging current drops under a predetermined threshold the charging is done. The charging current under constant voltage charging however, monotonically decreases from the get go so it usually takes much longer to obtain a full charge. But the good news here is that overcharging is unlikely as the charging voltage is fixed to the correct battery terminal voltage.

More details at Kerry Wong’s blog.

Check out the video after the break.