Thursday, November 29, 2012

Different Kinds of "High Voltage"

High Voltage!

Those words mean different things to different people in different industries.

In electric power transmission, high voltage is 35kV and above. In the U.S., the National Electrical Code (NEC) defines high voltage as anything over 600V.

In the digital world, a logical "1" high voltage can be a low as 3.3V, or even 1.8V. Older systems defined logical “1” as 5V, which really meant anything above 4.5V - many years ago.

International Danger-High-Voltage Sign

At VMI, high voltage means 1,000V or higher. In reality, 1kV is actually kind of on the low side of ‘high voltage’ around here when you consider that our diodes start out at 2kV reverse voltage (Vrwm).

Some of the rectifier assemblies – high voltage stacks and single-phase bridges – start at 2kV and go up to 45kV (per leg).

Highest of the high voltage is our power supply line. A 50kV, 10W output is the highest standard power supply VMI currently makes. Power supply design has lore all its own – as does rectifier assembly design, multiplier design, and anything at all to do with high voltage.

One thing we know is it pays to have respect for high voltage. It is truly an amazing natural phenomenon (think lightning). Maybe one day I will research that topic.

Teaser: Did you know that lightening could have a positive or negative charge?  Me neither. You learn all kinds of interesting things when researching a blog post.


Health and Safety Fact Sheet:  High Voltage (>1000 Volts) Electrical Safety and Injuries, (2009). Energy Recovery Council., retrieved 11/29/2012.

High Voltage., retrieved 11/29/2012.

High Voltage Warning., retrieved 11/29/2012.

Tuesday, November 20, 2012

More of "Happy Employees"

I have worked for Voltage Multipliers Inc. now for over 22 years, and am pleased to say that every year, in celebration of Thanksgiving, and in appreciation of all we have to be thankful for, VMI gives each employee (full time, part time, and temporary) a Thanksgiving turkey.

They are being delivered today.

And we are thankful.  For everything.

Thank you Dennis, John, and Ken.

Happy Thanksgiving, y'all!


Friday, November 9, 2012

Happy Work Force - The Start of Year 33

One of the great things about working at VMI is the fact that we all share in our successes.

Today VMI is providing lunch - to celebrate the start of 33 years in business - for all it's employees.

You know it's a good place to be when the first employee ever hired still works here.  A low turn-over rate means a lot of accumulated knowledge.

It's amazing how much goodwill can be generated with pizza, soda, and an extended lunch hour.

VMI opened it's doors on November 10, 1980.  Back then, voltage multipliers was the sole product line.

Over the last 32 years, VMI has expanded their offerings to include high voltage diodes, rectifiers, opto-couplers, power supplies, hybrid multipliers, and all kinds of other things.

We're really good at problem-solving too, so if you have a high voltage dilemma, call us.

Onward, and upward!  

Monday, October 29, 2012

Conventions and Expos - First Electronica 2012, then Pittcon 2013!

Coming up next month (November) is the Electronica show in Munich. 

But don't worry if you're U.S. based, and can't make it there.  You can visit us in March at the Pittcon 2013 conference and expo.  It runs from March 17-21st, 2013, and will be at the Pennsylvania Convention Center in Philadelphia, PA, USA.

VMI will be in booth #1517

Pittcon is the number one global conference and expo for laboratory sciences.  It's a great way to stay on top of your field and to network.

More info....

Friday, October 19, 2012

Cassini Launch Anniversary

Saturn and It's Rings
Date Published: December 22, 2005 - Photo source

It was 15 years ago today that NASA launched the Cassini spacecraft. It is still orbiting Saturn, and is expected to continue providing data up to September 15, 2017.

Please forgive me if I've mentioned this before, but VMI is very proud of our contributions to the Cassini project. VMI military grade high voltage diodes, voltage multipliers, or a combination of both were used on the Cassini craft.  We have also contributed to the following projects -

• Extreme Ultraviolet Explorer

• VDS Camera on the Solar and Heliospheric Observatory 
• GCMS instrument on the Huygens probe to Titan

• INMS instrument on the Cassini mission to Saturn

• XDL camera for the SUMER and UVSC instruments on the Solar and Heliospheric Observatory

• Spectroscopic camera for the Far Ultraviolet Spectroscopy Explorer

• MER (Mars Exploration Rover)

And we're happily working on more projects, too.  For more info on special applications, visit VMI's website.


Monday, October 15, 2012

First Man to Travel Faster Than the Speed of Sound

Felix Baumgartner did it!  He fell to earth more than 24 miles, and lived to tell about it.  Achieving more than 830mph, he exceeded the speed of sound in a free-fall that lasted more than 4 minutes, and was caught on film.

Pretty amazing!  

Thursday, September 20, 2012

Electronica 2012

Look for our logo!

Get your passport in still have enough time!  VMI will be at the 2012 Electronica show in Munich from Nov. 13th through the 16th.

This is Electronica's 25th year - the premier international trade show for electronics, components, systems, and applications.

We'll be part of the Protec GmbH booth, along with CalRamic Technology LLC - makers of high voltage ceramic capacitors.

Look for our logos.  We'll be in Booth 12-643.

Tuesday, August 28, 2012

Good-bye Mr. Armstrong

I was greatly saddened to hear of the death of Neil Armstrong over the weekend.  He was 82 years old.

I was ten years old when he and Buzz Aldrin and Michael Collins flew to the moon.  I remember walking outside, looking up at the sky and thinking, "Wow!  They are there right now!".  I didn't know much about politics or science or even life at that age, but I knew I was witnessing an historic event.  Although, honestly, I couldn't figure out WHY they didn't wait until the moon was full before making the trip.  Wouldn't it have been easier to land? 

He was a childhood hero of mine.  Unbeknownst to him, he and others like him played a part in my decision to go into the field of engineering so many years ago. 

I will miss him, and the comfort of knowing he walks among us. 

Bluetooth Controlled Lightbulbs

Speaking of light bulbs, there is a new light bulb coming to market within the next few months.  It can be controlled via an app on your smart phone, or tablet and has a range of 164 ft.  You can control the color, brightness, turn them on or off, or time them.  Think of the possibilities! 

Check out the video.

Blue tooth 4.0
Compatible with E27, E14 GU10, MR16, and MR11 socket types
3.-5.-7 W.

While it doesn't have much to do with high voltage diodes or power supplies, it IS innovative and fun.  In the long run, it may even be cost effective and efficient.  I'm keeping my fingers crossed.

Thursday, August 9, 2012

Curiosity and Space Projects

The recent landing of the Mars rover, Curiosity, is such a great feat of engineering!  Folks here at VMI came asking if there are any VMI products on the rover. 

They were asking because we have done space projects in the past.  Alas, this time the answer was "no". 

Past projects that VMI has participated in by supplying diodes or multipliers, for instance, include the Mars Exploration Rover (MER), the Cassini probe to Saturn, the Huygens probe to Titan, and more.

Mars photo credit - NASA

There's something about space projects that brings out the best in people.  It seems to transcend the little, day-to-day stuff.  We pull together; we work as a team towards a common goal - a successful project that's bigger than all of us!  No doubt there is a lot of hard work and heart break involved, but it's totally worth it.  We're all better engineers, managers, and production people for it. 

VMI has product on the mission due to launch Nov. 18, 2013 to Mars.  We're very proud of that fact.  You know we'll be following the launch.  We hope you'll do the same!  

Tuesday, July 31, 2012

A Promotion!

Congratulations to Daniel Deschenes, he has officially transitioned into Sales.  He's VMI's newest Sales Engineer. 

He's been with VMI for over seven years and he's a technical guy, so he knows a lot about VMI products and manufacturing processes.  Now that he's officially in Sales, you can expect to see him out and about visiting customers, attending trade shows, and juggling in his free time.

Feel free to give him a call (559.651.1402) or send him an email if you have any technical questions about high voltage diodes, opto-couplers, rectifiers, power supplies, or any and all VMI products.

Monday, July 30, 2012

Website Launch

VMI's website has a new look.  Check it out.  The logo has changed, and the main graphic is reflective of our products.  We'll be fine tuning it over the next few weeks, so if you come across a glitch, or inconsistency, please email me at K. Holland.  Feedback is welcome!  

Product photos, bottom l-r, formed lead high voltage diode, optodiode, optocoupler, CRT type power supply, X-ray tube type power supply

Wednesday, July 11, 2012

High Voltage Multipliers - MVM and PVM302P12

Why has the MVM series been replaced by the PVM series of high voltage hybrid multipliers?

PVM302P12 high voltage multiplier
 To be perfectly honest, the MVM series has been replaced by the PVM series because of low profitability.

The lack of profitability is a complex question, and there are no easy answers. Factors such as volume pricing (or lack of), process variations, data collection, and marketing, all contribute to whether a product is profitable or not.

In the case of the MVM, one of the largest issues was purchasing raw materials in low quantities. Take the following hypothetical situation. Say the MVM uses two lead frames per device, and they cost $5 each. The lead frame manufacturer has a minimum buy of 10,000 units per lead frame. If the device sells for $15, already 67% of the selling price is tied up in two components. You can see where this is going, yes?  This could be a problem when the device actually contains many more components.

Looking at it from a different point of view, say the total material costs, including the two lead frames, come to $15.00. Then, using the formula I use when I take my car to the mechanics to figure out how much it’s going to cost me to get my car fixed, which is to double the cost of the parts – then materials and labor for the MVM would come to $30.00. This is twice the original selling price. How many MVMs do you think we’d sell at that price? Exactly. The concern is we’ve priced ourselves right out of the market. Plus, to add insult to injury, if we build one part, we’re sitting on raw material inventory of $100,000 in lead frames alone. Even if we build 500 parts, lead frame inventory costs are still $95,000.

The moral of the story is that its a delicate balancing act between pricing, profitability, reliability, and manufacturability. In an ideal world, there would be no minimums, no set-up charges, no late deliveries, and 100% yield.  (Wouldn't that be great?!)

On the other hand, if that were the case, then a lot of us would be out of a job.  (Sigh)

Oh, by the way, the PVM family does not use lead frames.

Tuesday, July 3, 2012

High Voltage Diodes in High Voltage Multipliers

The illustration below shows a six stage, series, half-wave multiplier. This is a fairly simple design that utilizes high voltage diodes and high voltage capacitors.

Six-stage High Voltage Multiplier

The diodes are axial-leaded, glass bodied; the capacitors are coated-and-leaded, single layer ceramic. The end product is encapsulated, so all you’d see is a ‘black box’ with leads, or some type of terminations, coming out of it.

Typical applications include CRT type displays used in cockpits, and even the old-fashioned analog oscilloscopes (remember those?). They work well in instrumentation because low levels of noise and excellent regulation are achievable.

The nice thing about these multipliers is they are not limited to just caps and diodes, but can include feedback resistors, filter networks, multiple outputs, voltage taps, and more.

Many different topologies are possible besides the more common Cockcroft-Walton multiplier. Full-wave multipliers, parallel multipliers, or combinations of the above are all possible.

Custom features include ripple and regulation voltages, physical dimensions, terminations.

Give us your input voltage and output voltage, and we’ll do the rest.

Thursday, June 28, 2012

Anode vs. Cathode in a High Voltage Diode

SMF6533 High Voltage Diode with Cathode Band
SMF Type High Voltage Diode w/ Cathode Band
VMI’s high voltage diodes almost always include a marking of some type to indicate the cathode end of the device. Sometimes the cathode is indicated by a band, or one or more dots.

Distinguishing between the anode and cathode end is important when the diode is under test or part of a circuit.

Formed Lead High Voltage Diode with Cathode Band
Formed Lead High Voltage Diode w/ Cathode Band

There are two main conventions when dealing with current. They are the engineer’s convention, and the physicist’s convention. Neither is incorrect, it just depends on your definition of ‘current flow’. For the following discussion, we assume the engineering convention - that is, current will flow from anode to cathode or from positive to negative. A diode will block current flow when the cathode becomes more positive than the anode.

High Voltage Glass Body Diode with Cathode Band
Axial-leaded High Voltage Diode w/ Cathode Band
If you want a diode to normally conduct in a positive current, but insert the diode so that the current sees the cathode side first, the device will block current and it will look like you have an open circuit.

Likewise, if you want the diode to normally block, but insert the diode so the anode side sees the current first, the diode will conduct, and you might think you have a short.

 Just a few tips to the wise….contact VMI if you have any questions about high voltage diode anode/cathode conventions.  It can be a little confusing sometimes.    
For a quick reference, feel free to refer to the figure below that ties anode/cathode to blocking and conducting states.

Conducting and Blocking High Voltage Diodes

Tuesday, June 26, 2012

Deer-in-the-headlights Freeze

image credit

I know I need to make a blog entry, but I have a confession to make. I have had ‘writer’s block’ for going on two weeks now. 

To make matters worse, not only have I been suffering from writer’s block, I cannot even come up with a suitable topic to write about. Maybe if I could do that, I could create a reasonable blog post! 

(Care to share your ideas on potential voltage multiplier, high voltage component blog posts?  Is there something you'd like VMI to address???). 

Blogging is important in making and keeping business and social connections.  It is a wonderful avenue for providing better information to our customers.  That knowledge, combined with the anxiety of being stuck in time, can really, really, really create a lot of pressure, ya know?

Of course you know what I'm sayin'!  Most all of us experience external pressure from time to time – some of us more often than others. I am lucky in that most of the stress I feel is self-inflicted by way of artificial deadlines, impossible (or nearly so) goals, sleep deprivation, and over-scheduling.  

This entry doesn’t have much to do with engineering, high voltage diodes, or designing new power supplies, except it does have things in common with life in general.

Sometimes we need to take time to sharpen our sword, to take the pressure off, to take a breather…..all in the hopes that we’ll come back sharper, stronger, and healthier than before.

Here’s hoping that the next blog entry will be tied more closely to high voltage diodes, power supplies, and life in general.

How do YOU get over your fear of the blank, white page, or the design deer-in-the-headlights freeze?

Monday, June 4, 2012

Invisible Helmet for Bicyclists

Kind of like an airbag for your head, these bicycle helmets are beyond state-of-the-art!  They are INVISIBLE!  In the photo below, the view on the left shows the model wearing a collar.  On the right, the actual helmet is demonstrated. 

For all practical purposes, the helmet looks like a collar.  It is worn around the neck.  A micro controller monitors angular and linear momentum from sensors positioned in the device. 

This is also a great example of technology meets user feedback.  The project largely came about because people do not like to wear bike helmets despite studies clearly demonstrating they save lives.  A helmet-in-a-collar approach addresses everything from helmet-hair to bulkiness, to hard to carry around. 

The helmets are manufactured by Hövding.  They conform to EU safety regulations (CE-marked) and can be bought in Europe through

They sell for 3998 SEK, or approximately $560, depending on the exchange rate. 

How cool is that?  No more helmet-hair!  Do they make them for motorcycles or scooters? 

Too bad they probably don't use VMI high voltage diodes.  Maybe when they incorporate night vision capabilities, they might use some of our hybrid multipliers.  How 'bout that for a kick?! 

Wednesday, May 30, 2012

VMI is on Mars!

Just in are photos from the Mars "Opportunity" rover.  They are awesome!

VMI is proud to say we have provided standard high voltage multipliers and high voltage diodes for many NASA projects including MER (Mars Exploration Rover).  More info

The photo below uses 'false color' to enhance subtle color changes.  This helps scientists to identify materials of different compositions, but can look a little off to our eye.      

Contributing to space research and providing products for such demanding environments makes us better.  We inevitably increase our knowledge base and improve our manufacturing processes.  It's a win-win situation. 

How many commercial products can you think of that have roots in the Space Program? 

Friday, May 25, 2012

Many of us will have next Monday off from work in honor of Memorial Day, including the folks at Voltage Multipliers, Inc.  

Memorial Day has been around in one form another since the mid 1800. It is a Federal holiday observed in rememberance of American war dead.

Here are a few things you might not know about the holiday.

• Memorial Day is observed on the last Monday of May.[1]

• The first known observance of a Memorial Day-type observance was in Charleston, South Carolina on May 1, 1865 in commemoration of Union Solders who died in the Civil War.

• Ironton, Ohio, lays claim to the nation's oldest continuously running Memorial Day parade. Its first parade was held May 5, 1868, and the town has held it every year since. However, the Memorial Day parade in Doylestown, Pennsylvania, predates Ironton's by one year. [2]

• By the early 20th century, Memorial Day was an occasion for general expressions of memory, as people visited the graves of their deceased relatives in church cemeteries, whether they had served in the military or not.

• Over time, Memorial Day became a long weekend increasingly devoted to shopping, family gatherings, fireworks, trips to the beach, and viewing local parades.[3]

• Traditional Observances

         o On Memorial Day the flag is raised briskly to the top of the staff and then solemnly lowered to the half-staff position, where it remains only until noon. It is then raised to full-staff for the remainder of the day.[4] The half-staff position remembers the more than one million men and women who gave their lives in service of their country. At noon their memory is raised by the living, who resolve not to let their sacrifice be in vain, but to rise up in their stead and continue the fight for liberty and justice for all.

         o A moment of remembrance takes place at 3 pm local time.

         o Volunteers often place American flags on each grave site at national cemeteries.

         o Memorial Day is generally associated with the start of the summer season, and as such, a popular and traditional inauguration is holding an outdoor barbecue.

         o The National Memorial Day Concert takes place on the west lawn of the United States Capitol. The concert is broadcast on PBS and NPR. Music is performed, and respect is paid to the men and women who gave their lives for their country.

Enjoy your holiday weekend, and be safe!

1. ^ 36 U.S.C. § 116
2. "Doylestown Hosts Oldest Memorial Day Parade in the Country". CBS News. 29 May 2011.
3. ^ Matthew Dennis, Red, White, and Blue Letter Days: An American Calendar (2002)
4. ^ "How and When to display the US Flag at Half Staff". Retrieved 2011-05-Remembrance days


Wikipedia, the free encyclopedia, Memorial Day,, retrieved 5/25/2012

Monday, May 21, 2012

Watts a Lumen? (Pun Intended)

What to look for in a light bulb just got easier with the explanation of Watts and Lumens in this blog entry by John Chu is a Senior Communications Specialist at the U.S. Department of Energy.

Thursday, May 17, 2012

See you at the 2012 ASMS Conference

Missed us in Baltimore or Germany?  Catch up with Karen S. and Daniel D. at Booth 16 for the 60th American Society of Mass Spectrometry Conference on Mass Spectrometry and Allied Topics Vancouver, BC, Canada May 20 - 24, 2012

Wednesday, May 16, 2012

Sun Spot Babies (Not What You Think)

I'm dating myself here.  Besides the kind that appear on the back of your hands as you age, when I think of sun spots, the old Bob Seeger "Sun Spot Babies" song comes to mind.  But the fact is, the sun has been around a lot longer than either Bob or me.    
Dr. Tony Phillips, Credit: Science@NASA

According to Dr. Tony Phillips, the sun is finally waking up after taking a nap since 2008. Solar storms are on the increase as we begin Cycle #24. In honor of the uptick in solar activity, here are a few sun filled facts.

1. About every 11 years, the sun reverses magnetic polarity. It’s north magnetic pole becomes the south magnetic pole, and vice versa. (1)

2. The sun rotates on its axis once every 25.38 Earth days or 609.12 hours. (1)

3. If you weighed 150 pounds on Earth, you’d weigh 4,200 pounds on the sun. The sun’s gravity is about 28 times that of Earth. (1)
4. Communications and electrical systems on earth can be severely disrupted by solar flares. (1)
5. There are sometimes "Mock Suns" (parhelia) which are called Sun dogs because they follow the Sun around. These Sun dogs are usually seen as bright spots on opposite sides of the winter Sun. (2)
6. If the earth were the size of a quarter, the sun would be as large as a nine-foot ball and would be located a football field distance from the earth. (3)
7. It takes thousands of years for the light to travel from the core, where it is created, to the surface of the Sun. Only eight minutes more from there to us. The light you see now was created when the first Homo Sapiens started appearing. (4)

8. With our super cool telescopes we can see stuff on the surface of the Sun that is 80 km (50 miles) long. Considering the diameter of the Sun, that´s the equivalent of seeing the Lincoln Memorial Reflecting Pool on Earth. (4)

9. The sun seems to be a male god in the cultures close to the Equator, and female in the northern ones. The sun is always opposite the moon.  (4)

10. The sun vibrates, but because sound does not travel through a vacuum (space), no one hears it.  (4)
11. The sun has sun quakes that propagate through its entire surface in seconds. (4)

12. In the outer atmosphere of the sun, stuff moves along magnetic lines. It is like if you could only move towards or away from your refrigerator.  (4)

13. The upper part of the solar atmosphere is much hotter than the surface.  No one knows why.  Normally the upper part of an atmosphere is colder.  Think of the earth - the further away from the planet you get, the colder it gets.  (4)

     So how does this relate to high voltage diodes? Well, you’ve heard of EMP, right? Electro-magnetic pulses. The sun can generate them. When that happens you need a radiation hardened device, or one that can absorb a lot of energy – like VMI’s E-Zorb diodes. Standard silicon diodes are susceptible to over voltage conditions whereas the E-Zorb diodes can better handle higher reverse power pulses.  



Tuesday, May 15, 2012

We're Nominated! Kind of.

We are thrilled!  VMI has been honored as a supplier to our customer who is a finalist in the Radiological and electromechanical devices category of the 2012 Medical Design Excellence Awards (MDEA) competition.  Up for nomination is a system that uses one of our high voltage power supplies.

The 2012 MDEA winning products will happen Wednesday, 23, 2012 at the Philadelphia Marriott. 

• The 2012 MDEA-finalists, and their suppliers, will be honored for their innovative contributions to the medical device industry.

• Dr. Thomas Fogarty will receive the prestigious 2012 MDEA Lifetime Achievement Award for his contributions over a long career. Dr. Fogarty founded 33 medical device companies and holds 135 surgical instruments patents. He has been inducted into the National Inventors Hall of Fame and has won countless other awards including the Lemelson-MIT Prize for Invention and Innovation.

Soooooo, keep your fingers crossed, and root, root, root for VMI.

Thursday, May 10, 2012

New Products - Soon!

Keep an eye out for new, high voltage diodes coming your way.  We're expanding the SXF family to include higher voltages and current.

They're great little packages - high voltage in a minature footprint, and easily pick-and-placeable.

They're really kinda cute!

More later...

Friday, May 4, 2012

Better "Made in Space" than "Lost in Space"

How would you like to have a product “Made in space”? Personally, I’d LOVE to have something like that stamped on a product somewhere. The whole idea is fascinating.

And that’s exactly the response the European Space Agency (ESA) hopes to get with their branding campaign.

Still in the planning stages, the ESA is working towards increasing public awareness of the value of the International Space Station (ISS), space research, and space manufacturing. Many products and technologies actually go back to space research. These include memory foam (think Tempur-pedicTM type beds), in-ear thermometers, and even the laser used in DVDs. The average time from research to commercial development is three to five years.
Image Credit:  NASA

Up and coming new technologies include alloys for jet engines.  Signficantly lighter and stronger than alloys currently used, the new alloys could result in significant weight reductions, which in turn would reduce consumption, lower costs, and use less non-renewal resources.

Another breakthrough hovering on the horizon is a version of ionized gas used to kill harmful bacteria. This could be critical in efforts to fight superbugs.  As more and more antibiotics lose effectiveness, doctors will need more tools in their medical kits.

All in all, considering the benefits the world has received from space exploration, it's a good investment in the future. 

Tuesday, May 1, 2012

Visit VMI at Booth 12-643 PCIM International exhibition and Conference for Power Electronics, Automation, Motion Drives & Control + Power Quality May 8-10 Nuremberg Germany.  Check us out!

PCIM 2011 Photo

Diode vs. Rectifier

According to Wikipedia, a rectifier is defined as, ”An electrical device that converts alternating current (AC), which periodically reverses direction, to direct current (DC), which flows in only one direction. The process is known as rectification. Physically, rectifiers take a number of forms, including vacuum tube diodes, mercury-arc valves, solid-state diodes, silicon-controlled rectifiers and other silicon-based semiconductor switches". 1

Sometimes the term, “rectifier” is used to refer to a discrete diode, and technically, it is correct.
1N6535 Discrete Axial-leaded Diode

At VMI, our terminology varies a bit from Wikipedia’s. It is still correct, but not as common outside the manufacturing environment. The differences in usages probably stems from being a manufacturer of both discrete diodes and diode assemblies, and may have evolved as a kind of verbal short-hand. Now the terms are firmly entrenched throughout the sales, marketing, engineering, production, and QA departments.

SMF6525 Over-molded Diode

Okay, so what’s different? Here at VMI, a diode refers to a discrete device. It can be over-molded with epoxy, as in our K-body diodes (K100S), or SMF6525, or a glass-body type device such as the 1N6535. There are generally two terminations – an anode and a cathode. 

The term “rectifier” is short for ‘rectifier assembly’, and is usually constructed using multiple diodes. Rectifier assemblies include high voltage ‘stacks’ (a.k.a. a high voltage stick like the SPJ series), single phase or three phase bridges, doublers, center-taps, and so on. A rectifier assembly generally has multiple diodes, or more than two terminations. 

Not to worry though. If you call up and ask for a high voltage rectifier, we’ll know what you mean.

Friday, April 27, 2012

"Alien" Roots - Are We Witnessing the Beginning?

I don't know about you, but when I first went to see the Alien, the 1979 sci-fi horror film, I was, well, horrified.  That movie scared the daylights out of me. 

Theatrical Release Poster by Bill Gold
Today's article is about a company, a real company of billionaires, engineers, and scientists, outlining details to mine asteroids for water, minerals, and such.  If you're not familiar with the plot of Alien, let me say, The Company plays a transparent but evil part in the movie.  

Commercial enterprises don't always have the best interest of their employees at heart, and that was definitely the case in the movie. 

Anyway, check out the article.  Could it be we're witnessing an historic event?  Okay, maybe not historic, maybe more 'ironic'?  Plus, I'm kind of curious - does anyone 'own' the asteroids?  I can see several legal and ethical issues that might come up.  Surely people more in-the-know than me are addressing them.  I can only hope....   

If you've ever wondered how we get there from here, we might just be witnessing the first tentative steps.

Enjoy the article! 

Tuesday, April 24, 2012

JFK to London in One Hour or Less?

How would you like to fly from NY to London in an hour?  It sounds wonderful, doesn't it!  We could visit with our internal sales representatives as frequently as needed, or hand deliver high voltage diodes, even.   

Okay, seriously now, check out the article on passenger and cargo air transport.  It might be a little early to book your flight, but prototypes are expected for some designs as early as 2020.  2020 is not that far away. 

How would you take advantage of global flight times of 2 hours or less?

Photo Credit:  NASA

Friday, April 20, 2012

What Good are X-rays? Aren't They BAD for Us?

X-rays are used for a lot of different things, including medical diagnosis and treatment – CRT and CAT scans, fluoroscopy (i.e. coronary artery blockages) for diagnosis, and radiation treatments for cancer.

X-rays are part of the electro-magnetic spectrum which includes visible light we see every day. Visible light includes ultra-violet on one end; infra-red on the other.

x-raysThe X-ray spectrum is beyond the ultra violet range, and is bordered on top by the gamma ray spectrum.

X-ray radiation frequencies ranges between 3 x 10^ 17 and 3 x 10^19 Hz; wavelength ( lambda), ranges between 1 x 10^-11 and 1 x 1^-18 meters. X-rays are characterized by high energy which makes them suitable for interacting with electrons on the atomic level. It is largely this feature that makes them useful in detecting metals, or bombarding and penetrating the human body.

Applications include

• Security (airport scanners, truck scanners, border patrol)

• Medical Diagnosis (CRT, CAT scans, fluoroscopy)

• Medical Treatment (radiation treatment)

• Spectromicroscopy – used to detect paint layers, and pigment degradation in artwork masterpieces

• Crystallography – used to analyze minerals and metal alloys

• Astronomy – used to find and identify sources of x-rays in the universe

• Portable medical and dental x-ray systems answer the questions, x-rays can be harmful or beneficial.  Modern technology has put them to good use.  Sometimes the applications are good, sometimes they are controversial. 

Either way, I think they're here to stay.  What are your thoughts?

Monday, April 16, 2012

Latest Solar Storm 2012

Great article by Jeffery Bausch on the latest solar storm happening RIGHT NOW, and five things you need to know.  Think they won't bother you?  Think again.....They might, especially is you use the Power Grid, or land based phone lines. 

Solar storms can effect -
  • Satellites
  • GPS devices
  • Space shuttle and space station activities
  • High-altitude polar flights
  • Electric power distribution
  • Long-line telephone communication
  • HF radio communication
  • Pipeline operations
  • Geophysical exploration

Photo credit:  NASA/SDO/AIA taken March 10, 2012

In the photo above, an active region has been moving from left to right since March 2, 2012.  So far it has generated three X-class flares and numerous M-class flares. 

The disturbances are electro-magnetic in nature.  Diodes and other components can be radiation hardened - meaning they're not as susceptible to EM pulses.      

Have you noticed anything different in your electronic or electrical devices since March?

Tuesday, April 10, 2012

Pittcon 2012

Pittcon Show

The results are in! There were 15,754 visitors to the world’s largest laboratory science conference and expo. And VMI was there! Margaret and Daniel were available to handle questions on high voltage diodes and other VMI products. High voltage opto-couplers are especially hot items for mass spectrometers and other instrumentation.

Pittcon is the event for scientific specialties such as spectroscopy and chromatography. Attendees were from many different industries including education, manufacturing, environmental, agriculture, biotechnology, pharmaceuticals, and more.

Next year (2013), Pittcon will be held in Philadelphia, PA.

Pittcon 2012 

Wednesday, April 4, 2012

Optimum Stress

Curve from zenstorming  
I first came across the Yerkes-Dodson curve a couple years ago.  It popped up again recently. 

The first time it was related to arousal levels in students taking tests in college.  Basically, what it says is there is an optimum stress level for a test-taker.  Too much or too little stress, and the test-taker performs below his or her capabilities.

The second time around, it was in reference to work-loads.  With several fast-paced projects going on, the stress level rises.  You can see it on the faces of your co-workers (and maybe you're own), if you know what to look for.  Usually you don't have to look hard.  What you don't know is just how much stress they're under or where it's coming from.  What you do know is, they're feeling the pinch. 

Different people have different ways of handling stress.  If one person is under-stressed, maybe they feel they're not busy enough.  They go looking for things to do, projects to work.  They FIND something to do that interests them. 

Short-term over-stress is one thing. Chronic over-stress is an entirely different animal.  In short-term over-stress, a person knows it's temporary.  Maybe the push is to get something shipped out the door - a new prototype - in under four weeks.  The goal is clear, possibly unreasonable, maybe almost impossible.  But it's time limited. 

On the other hand, chronic over-stress can take a toll in the form of burn-out, and it creeps up on us.  You know what I'm talking about - it's hard to get out of bed in the morning, or get excited about a new project because you're just not quite up to the challenges.  It requires more energy than you have.  We've probably all been there at one time or another in our lives.  The best advice I've come across to deal with burn-out is to start simplifying, cutting back, and prioritizing.  Figure out the really important things, and work on those first.  Take baby steps.  If your goal is to have a more balanced work-home life, start by leaving work one day during at the week 'on-time'.  If that works, start there and expand.

Just my two cents worth.

What's the best advice you've heard about preventing job burn-out?        

Thursday, March 29, 2012

Why You Should Go Clean Your Room Now, or Just How Much Do Humans Shed?

The "With You in the Room, Bacteria Counts Spike" article discusses an experiment carried out on a ground floor university classroom in use that analyzed bacteria and fungi, surprising results.

The principle investigator was Jordon Peccia, an associate professor at Yale.

Clean-room anyone?  Or maybe a personal high voltage air purifier. 

Monday, March 26, 2012

Single atom working transistor
How cool would it be to have a high voltage diode the size of a single atom?  Is it possible?

Maybe some day....They're already doing it with transistors.  The University of South Wales has created a working single-atom transistor

It isn't in production, probably won't be any time soon, and there are certain design considerations when dealing with high voltage diodes.

But the single-atom transistor may be just the needed break-through needed to keep up with the predictions of Moore's law.

Defense Security and Sensing Conference 2012

Visit VMI and see our new booth 1535 at Defense, Security, and Sensing 2012 Conference will be held 23 - 27 April 2012 at the Baltimore Convention Center, Baltimore, Maryland.

Thursday, March 22, 2012

Multi-junction High Voltage Diodes

VMI Multi-junction High Voltage Diode
 Once in a while we get a customer inquiry about connecting diodes in series to get a higher reverse blocking voltage in their application.

Sometimes they express concern about one diode having a faster Trr than the others. The thought is that when the applied voltage starts to switch negative, the faster diode would hold off the entire PIV until the rest of the diodes in series could catch up. The question is whether it would cause a catastrophic failure by shorting out first one diode, then the next, and the next, and so one, until the whole string failed.

Fortunately, that is rarely the case. For one thing, reverse voltage does not happen instantaneously. There is a slew rate, and if the reverse recoverytime, Trr, of the diode is sufficiently fast for the application, it will block before the full reverse voltage is experienced, thus preventing a cascade of failing diodes.

Secondly, anytime you work with a diode greater than roughly 1200 Vrwm, there is more than one diode junction in the package. A 10kV diode used multiple internal junctions. It is the rough equivalent of connecting ten single junction diodes in series, in a much, much smaller package.

Multi-junction diodes are made from the same wafer and diffusion lot, so variations in Trr are kept to a minimum. With continuous improvements made to the diffusion and manufacturing processes, process variations have been further minimized. All of which goes towards improved product reliability and quality.  And you know that's good for you!

Thursday, March 15, 2012

Great article from IEEE about the brewing controvery over China's export policies on rare earth metals (think magnets), tungsten (think semi-conductors), and molybdenum (think stainless steel, water & food & hospital distribution systems). 

Effected industries include automobile manufacturing, electronics (including semi-conductors), oil & gas production, medical equipment, and more. 

China has the largest Tungsten reserve.  A distant second is Russia, followed by Canada and the U.S.  The last time the US produced Tungsten was in 1994.  The last time the US processed Tungsten concentrates was in 2004*. 

Tungsten is used extensively in making cemented carbide parts (cutting and wear-resistant materials for metalworking, oil & gas production, construction).  It can also be found in lamp filaments, electrodes, electrical and electronic components, tools, alloying metals, chemical catalysts, and pigments.

Of course, the world is busy working on alternative materials and sources.  Time will tell.
*Source:  U.S. Geological Survey, Mineral Commodity Summaries, January 1998

Tuesday, March 13, 2012

High Voltage TWT Power Supply Guidelines

I was doing a little research on design considerations for TWT power supplies, and came across this report from NASA.

This is an analysis of an 11kV High Voltage Power Supply that apparently exhibited evidence of a corona-induced short in the high voltage connector. 

Figure 2 - High Voltage Compartment Construction - NASA PD-ED-1202
Included in the report is a photo of a partially de-encapsulated unit.  It's hard to say for sure, but it looks like they used epoxy diodes?! 

You know how the internet is....down the rabbit hole I went, and, well, one thing let to another, and before I knew it, I came across even more design practices from NASA.

As for researching TWT power supplies, I was looking to confirm guidelines for specifying high voltage diodes.  I seem to recall hearing that diodes are susceptible to damage on the high voltage end of the multiplier because of arcs from the tube.  TWT PS typically run hot and fast, and unless a diode has sufficient reverse power capabilities, it could spell trouble. 

Comments anyone?

Wednesday, March 7, 2012

DARPA program - Robot Cheetah Breaks Speed Record

This article provides interesting information on the DARPA funded project to create a free range running robot.  The robot cheetah video shows just how the M3 (Maximum Mobility and Manipulation) researchers were able to achieve speeds of up to 18mph.  That's incredibly fast when you think the fastest human on the planet might run a 3:30 minute mile, or 17mph.

Check out the article to find out where this is going.    

Thursday, February 23, 2012

High Voltage Test Data Gone Wild?

Nothing spurs data collection faster than a problem occurring in the Production line. As a company, we’ve gotten really good at gathering high voltage test data, product yields, process parameters, and all sorts of really good things.  The collection process continues to evolve in ease of use and sophistication. 

Having relevant data on hand helps to make informed decisions.  Without a doubt, it is a step in the right direction.  We analyze the data, make reports, create graphs, discuss it in meetings, formulate solutions, and implement plans until the problem either goes away or gets fixed.
Everyone knows how hard, if not impossible, to make good decisions without data.

The problem is, sometimes we forget to turn the data collection spigot off. As engineers, we move on quickly to the next project, and only look back when something catches our attention.

High Voltage Testing Data
Finding the right balance between collecting data for its own sake (as in, “just-in-case something happens and we need traceability”), and discontinuing data collection because the issue has been resolved, is difficult to achieve.

Something else to consider – how important is data collection if no one looks at the data? Collecting, analyzing, and reporting all consume expensive resources. Sometimes these resources could be better spent somewhere else.

How do you determine when, if ever, to stop data collection?