ed ro

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President

Ed Rodriguez was founder/CEO of Theta-J Corp(now the Clare division of IXYS Corp). In that role he developed the optical MOSFET solid state relay, now a global defacto standard in the telecommunications industry. He is a veteran of the power semiconductor, power supply and LED lighting technology industries.Early on, before becoming an entrepreneur, he was a product manager with Unitrode (now part of Texas Instruments.) Keynote speaker at 1986 MIT national conference on advanced power electronic technology, he has published dozens of feature articles in the leading technical trade magazines. He also has been noted in Forbes and Wall St Journal. He holds 22 patents with 8 pending, virtually all involving successfully commercialized products. In 2005 , he formed OptoThermal Technologies to focus on thermal management technologies related to high-power LED lighting.


ed ro

's contributions
  • 10.30.2013
  • That 60W-equivalent LED: What you don’t know, and what no one will tell you…
  • First of all there is ZERO safety or fire hazard if you use any 100 or 150 watt “equivalent” LED bulb in a table or floor lamp. That is because the LED version will actually use only about use about 15% of the watts of an incandescent of that actual wattage—so really only 15-25 watts !! You will find that a 100 or 150 watt –equivalent LED bulbs are still much larger and more expensive than today’s most popular 40 and 60 watt types—but heat or safety not an issue. Separate commentary---. Since my first remarks few years ago-dramatic change-- prices of a 60-watt-equivalent have dropped from the $8-10 range to today’s pricinginUS of $1.50 to $2.50 each at almost every mass merchandiser—a far faster drop than ever imagined. Has ended the CFL-versus- LED bulb debate. Today It makes almost no sense to buy a CFL which, even if only half the LED bulb price a) takes up 60 seconds for full brightness b) only lasts only 1/6th as long in very best of situations and c) has poorly specified accuracy on color temperature temperature(warm white, cool white etc) Furthermore, after 10 years of dozens and dozens of mfrs producing every conceivable kind of configuration, the industry has now settled very firmly into an A-19 standard shape almost identical to the long familiar incandescent bulb. It is a certainty that not a manufacturer in the industry is making a cent of profit on today's 40 and 60 watt residential LED bulbs but the high volume is giving them a volume base which translates into profitability for all their much higher priced industrial or special purpose types, such as Par 30, 38, candelabra types etc Ed Rodriguez www.optothermal.com
  • 06.14.2016
  • LEDs in stores could leave a bad taste in your mouth
  • I would flunk the Cornell researchers ( rookie grad students conceiving/doing the experiment?) for sloppy science. For any regular transparent or translucent quart, half gallon or gallon container of milk, any outside LED lighting is greatly attenuated at only 1/4" from outside container surface---- and, at one inch inside, there is essentially zero light penetration. This is really easy to test in a couple minutes (which I did). So any poured glass of milk, from a new container, in the worst case, will contain a mixture of at least at least 95% "good" milk with a max of 5% "imperfect" milk. So this is a make-believe problem- -unless consumers buying their milk in Petri dish containers. I am unaware of any supermarkets who sell milk that way. Looks like our better engineering schools are losing something off their fastball. Ed Rodriguez OptoThermal Technologies Inc
  • 04.20.2016
  • What you don’t know about LED light intensity curves for grow light apps
  • The challenge is not just to achieve a result but to do it while meeting cost thresholds for commercial practicality.There are optical methods to create grow light 45, 60 or 90 degree beam angles with less than 10-15% "received" light level variation across an entire grow bed but the cost is prohibitive for 95% of growers. The real intent of the piece was to point out how misleading the "light intensity" curves can be for so many commercial lighting products (LEDs, optics and finished lamps), not just grow lights. Not sure an Abbe reflector approach for an LED array would address any of the issues here. (from one who worked with many kinds of military radar parabolic antennas early-on in my career before I moved over to the semiconductor industry)
  • 10.08.2013
  • True or false: High-power LEDs don’t generate IR heat in the forward direction like a filament lamp
  • good to see that folks still reading these things. However, in these LEDs, nor any other commercial LED the material is gallium based, "NOT" silicon, so silicon defects not the issue. Since originally writing this I have become more educated on the subject, which indeed is very complex and the subject for discussion among those whose careers have refleced an emphasis on radiated energy--- really into the physics of all this. When and how IR is secondarily generated and manifests itself as forward directed heat with high power blue LEDs-- phosphor coated or not-- would be a great grad student project. My only caution to designers is to not take literally the idea,common 12 years ago, that LED's run cool and send "no" heat forward . Heat sinking the back side is a given but convective heat removal, heat coming forward , and potential IR heating of nearby things is not to be ignored. Moral of the story? Make sure, before putting a higher power LED lighting product into production , that all surface temps near the LED are close to what one thinks they are, no matter what your math has predicted.
  • 10.30.2013
  • That 60W-equivalent LED: What you don’t know, and what no one will tell you…
  • The reason your bulb does not work in horizontal position is going to be EXTREMELY SIMPLE reasons--such as the socket depth is a little deeper so tip of bulb does not make contact and you have to screw it in a little tighter to make cntqact-- and hopefully not break it--but that sometines happens with socket depths.There really is no mystery here and if I had your chandelier and bulb I would figure it out in two seconds. I assume that 1) your previous bulb, or a rgu7alr ncadescent bulb works OK in that hariznatal socket or 2) that bulb which doesn't work, "does" work in another fixture. I assume, snce you bought oin Amazon, you bought because of lowest price and that 1) it is NOT UL listed. If you really want to know what;s going on, go to Lowes and buy a similar candelabra bulb from Feit, Sylvania or Lowes'"Utilitech" brand, make sure !!!!! package says "UL Listed" or has that little UL logo, and try it. Buying "no name" LED lighting products of Amazon, in my opinion, is risky. I oftent do it for experimental purpose but would never install an LED bulb in a fixture in my home unless from known firm and UL listed. I have spent over 40 years as engineer and CEO in related tech industries, especially LED lighting in last 8 years, so, as my wife well knows, I don't fool around or try to save a buck when it comes to electrical things. I have advised my three sons, for their homes, accordingly on LED lighting and dimming matters.
  • 11.04.2015
  • Can GE's new LED bulbs help you get to sleep?
  • This GE announcement "reminds" me.... With all the breathless commentary over the last 5 years about the validity of the so-called Haitz Law and the constant march toward 300 lumens per watts--along with he breathless announcemetns over last 24 monthsr ago of over 200-250 LPW for LEDs ,by Cree and others.--------- if readers go to Hmee Depot and Lowes. and pick up latest "state of the art" GE Bright Stik or latest from Cree and Philips ,you will see lumen per watt figures under 70-80 LPW. So much for Haitz Law and the American consumer, Consumer led bulbs have changed little in terms of efficacy over the last 3 years. Lower prices are synonymous with using the bottom end of LED mfg distribution with the "good stuff" only finding its way into commercial lumenaires. There's a method to the madness. Ed Rodriguez
  • 10.30.2013
  • That 60W-equivalent LED: What you don’t know, and what no one will tell you…
  • Reader mentions that COSTCO shop light works OK. Makes sense. Today, many low cost, relatively low wattage, simple LED "fluorescent-tube-replacement" type products use a simple series string of many LEDs . along with a 15 cent bridge rectifier and a one cent resistor as a "ballast" instead of an LED power supply (aka Led "driver" or even the AC LED circuit" I had alluded to. The simple LED string, with dozens of cheap LEDs, with a resistor and rectifier, has relatively lousy power factor(but still OK per industry min standard) ,loses some efficiency and other properties but is really cheap to make and perfectly adequate for a low cost "basic function" shop light . Having no need for a capacitor in it would make it immune to that flashing characteristic,
  • 10.30.2013
  • That 60W-equivalent LED: What you don’t know, and what no one will tell you…
  • There are no such things as lighted switches which can work for you--neon or led.. The problem of course is that a "lighted switch" is never really off. It is "cheating" and powering the neon . and the neon typically acts like a 47K ohm resistor connected across the switch contacts, allowing a small charging current to flow and charge up large capacitor in the lamp internal power supply.As soon as the capacitor charges, there is enough power to momentarily turn on the lamp.No big deal and perfectly safe but indeed you have discovered an interesting "anomaly". The problem will not exist if you control a lamp or LED fixture having what is now called an "AC LED" direct-drive circuit--no internal power supply and no charging capacitor. Home Depot now sells low profile 10 watt ceiling mounted LED fixtures(made by Lithonia/Acuity) --about $20--with this circuit ( I have one here) , but there are not yet ( I don't think) any lamps readily available with this circuitry (for reasons I won't go into here)--Ed Rodriguez
  • 10.30.2013
  • That 60W-equivalent LED: What you don’t know, and what no one will tell you…
  • Regrettably ,maybe not. The one possible is to fnd, on Amazon or somewhere else a halogen E12 since it might have 20% more lumens, An LED or CFL rated for only 7-8 wattscoud easily give doi8ble the lumens, but the enclosed (sealed0 enlcosure woud caus the led or CFL to overheat or come close to the edge. A regular or halogen incandescent does not really need any air cooling and runs very hgot as part of its normal operating mode. You light fixture is sealed to prevent grese. etc from getting into its electrical socket. It absolutely is possible to design a 7-8 watt led lamp for this applications but nobody has becausue the demand is too small for low cost/off shore mfg where all 99% of LED bulbs are now made.ONe last option--maybe--- your E12 isa cadelabra base.If you have you hardware stgore order a candelabra to medoum base 'adapter, you coud screw ina 60 watt incandescent and get 50% more light.--- if that bulb would fit. Yes the 60 watt is a little more heat but you fixture would probably safely handle it. If it were life and death to have more light, this is what I would do and then drill some holes in side of fixture to let in a little air to cool things a few degrees fr more of a comfort factor. There., simple question--convoluted answer.
  • 03.10.2015
  • Can you use supercaps to power electric vehicles?
  • I have indeed been fascinated myself by the "concept" of super caps.Because these days I am heavily involved in all kinds of advanced LED lighting technologies, I necessarily have looked into the feasibility/possibility of using super cap energy storage for solar based, "basic' lighting where utility power is just not an option-- eg third-world bare bones. where the obtaining of replacement batteries could be problematic (forget about solar streetlight apps--totally out of the question). Regretfully, after some serious homework (as a past founder/CEO of two high tech firms , I know how to do real world cost manufacturability analysis) I found that teh cost premium or using suepr caps just puts cost into stratosphere.--10 times what a rechargeable battery system would cost.Imnpossible to justify unless an EXTRAORDIINARILY specialized application. Super caps--great for very high current,short duration/low impedance apps but not for anythng of continuous use. Will graphene bases supe caps change the equation,? maybe in 20-25 years?--maybe. Bottom line-- because of OVERWHELMING cost issues there really are no super cap applications for replacement of rechargeable batteries. Ed Rodriguez, OptoThermal Technologies