Wednesday, December 31, 2014

Trr Testing in High Voltage Diodes - to Mil Specs

During the research phase of a project I was working on, I came across a public domain Mil-Std method for testing reverse recovery time(Trr) in high voltage diodes.

What was interesting was the number of conditions the test looked for, including jitter, soft knee(rounded transition), slope, drift, double break, double trace, discontinuity, and snap-back.

Of particular interest to me was, years ago, I would occasionally see the Vbr of a DUT snap back. That usually meant a junction arced.  You could see it on the oscilloscope.  Usually the remaining junctions could withstand the same applied voltage because the reverse current was limited, thus limiting the heat dissipation.  Otherwise, the diode would have gone into thermal runaway.

Anyway, below are a few generic graphs illustrating some of the more interesting reverse voltage breakdown failure modes.



During Trr testing, VMI tests for all of the above conditions, and more.  100% of VMI diodes are Trr tested.  It is not a sample test.  It's part of our total commitment to quality,  

Tuesday, December 30, 2014

Voltage Multipliers Inc. - Holiday Schedule

Here in the States, Halloween, Thanksgiving, Hannukah, and Christmas are over.

Looking forward to New Year's, VMI will be closed January 1, 2015.

A reduced crew will be here January 2, 201 - a Friday.

We'll be back in full swing on Monday, January 5th.

In the meantime, have a Happy New Year!

May you find peace, happiness, health, and prosperity in the coming years.


Friday, December 26, 2014

New 50kV Optocoupler - Coming Soon

Look for VMI's upcoming high voltage optocoupler in 2015.

Featuring a reverse standoff voltage of 50kV (yes, 50kV), it will be slightly larger than the 15kV OC150.

Encapsulated in optically clear material, the OC50 will feature high voltage isolation, stable high voltage gain, and will be RoHS compliant.

Look for it in 2015.
15kV Optocoupler.  Coming soon - the 50kV OC50!

In the meantime, if you need a high voltage optocoupler between 2.5kV and 25kV, check out VMI's product line.


Thursday, December 11, 2014

Environmental Policy Promotes High Voltage Diode Availability

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It’s time to renew our annual Safety Training certifications. Every employee is required to read and understand safety procedures related to the performance of his or her job.

Depending on your job description there may be a few procedures to learn, or there may be many. I just completed mine, so I’m good to go, and happy to have completed the training.  

Because of the business VMI is in - manufacturing high voltage diodes and assemblies - safety issues can be closely linked to environmental issues.

VMI uses many different materials in many different processes.

In a recent meeting VMI’s policy on manufacturing environmental issues came up.  It wasn't the primary focus of the meeting, but it was clearly a priority.  

To summarize, VMI works very hard to stay within local city, county, and state guidelines. VMI has long demonstrated a strong commitment to environmental concerns by its proactive attitude, providing dedicated resources, and following up with actions and procedures. VMI goes the extra mile by doing the right thing, by exceeding the level of expected compliance. For instance, VMI’s goal is not to keep emissions at the maximum allowable level, VMI’s goal is to eliminate them.

Why? Because we can, because it’s sustainable, and because, in the long run, it’s the right thing to do.  

VMI has been around for more than 35 years.  Sustainability in practices, procedures, and manufacturing promotes continued longevity.  The long-term gains far exceed  short-term gains.  We're in it for the long haul.      

I love a company that walks the talk!

Wednesday, December 10, 2014

How Did the End of the Semester Become the Best?



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The semester is just about over.  The Basic Electronics class I teach at the local Junior College is just wrapping up.  All that’s left is the final exam.  The material covered everything from Ohm’s law, caps, resistors, diodes, and inductors, up to and including semi-conductors.  As is typical with college classes, we could have spent twice as much time covering the material, but alas, time was short.

The last two labs were dedicated to the "culminating experience".  The assignment was to build and debug a circuit using the 555 timer.  The timer is used to control two flashing LEDs.  
The students struggled a little – many had never soldered before – but they clearly demonstrated a grasp of the concepts presented in class.  During the last class, there were lots of discussions about resistors, ratios, current ratings, pin-outs, Ohm’s law, and strategies for debugging the printed circuit board when things didn’t go exactly as planned. 

The students encountered just about every possible scenario from the manufacturing world.  There were cold solder joints, oxidized pads, mislabeled components, and even WRONG components (I’m still trying to figure out how that happened). 

The really cool part of the whole experience was seeing those ear-to-ear smiles when they finally got their project to work.  All their hard work paid off – in SMILES. 
That's what it's all about.  

Tuesday, December 9, 2014

3 Things You Don't Want to Hear About Stressful Holidays


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The holidays are always a special time of year.  For some, that’s great, for others, well, not so much.

I hope you find yourself in the first category, but for those of us who don’t, here are a few things I’ve incorporated in the last year to help make the holidays a little happier –

1.      Don’t stress about trying to please everyone.  It isn’t going to happen.  You can please some of the people some of the time.  You can’t be in two places at the same time, so prioritize the best you can.  Blended families, in-laws, dysfunctional families (admit it, every family has at least one “difficult” family member), impossible schedules…..Maybe you’re on the flip side – a small family, or no family, and want a big celebration.  Do your best, and don’t berate yourself if you don’t get it perfect. 

2.      Re-examine those expectations.  Do you really have any control over whether Aunt Edna limits herself to two glasses of wine, or whether Cousin Sue recites the entire dialog of “Forrest Gump” at the table?  In case you’re wondering, the answers are "No", and "No".  Don’t stress.  You'll get another opportunity to do it differently next time.     

3.      Plan ahead, and know that travel delays and snow storms, are gonna happen. 
 
At work, I’ve come to expect that things will either slow down to a snail’s pace because people are out, or it accelerates to beyond unbelievable because people are out.  It just all depends.  It helps to keep a clear perspective.  There are always exceptions, but most things are not as ‘urgent’ as we’d like to believe.  Ask yourself if what you’re working on is truly urgent.  If yes, take a deep breath and keep working.  If not, well, take a deep breath and keep working, and rest a little easier knowing that that sense of urgency is just that – a sense.      

I've come to believe the key to a happy holiday is to stay calm and stress-free.  A lot of the pressure we feel is self-induced.  Learning to recognize it can help keep us healthy, and happy.   

Happy, Healthy, Holidays! 




Friday, December 5, 2014

How Right Can Holidays Go?



Happy Holidays! To You and Your Family


Happy Holidays from Voltage Multipliers Inc.



VMI will be closed for the Christmas holiday on Wednesday and Thursday, December 24th and 25th. Some of us will be back in the office on Friday, Dec. 26th.

We will also be closed Dec. 31st and January 1st, 2015 in order to start the new year off right.

Wishing you happiness, health, and prosperity, in the new year ahead, May everything 'go right' for you during the holidays!

Sincerely, Team VMI