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

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  • 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
  • 10.30.2013
  • That 60W-equivalent LED: What you don’t know, and what no one will tell you…
  • lightalog--few more comments--- At 7-8 watts you are right on the edge of acceptability, I will comment as though "I " were the one doing this-- and I am intimately familiar with all the aspects of how an led or internal power suppy may fail on the basis of thermal issues.. First of all, in a high ceiling room, there will tend to be ever so slightly more air currents than near floor level--- a good thing. The slightest air movement can drop the bulb temp a few degrees making it seem like the wattage (and consequent heat generation) is 5-10% lower than it actually is.. Needless to say , if you have a fan on, in the vicinity. that is a big help. Again, if it were me, I would say the air circulation caused by the fan, even if not great, would convince me that led bulb, at 7-8 watts, is going to be OK,maybe operating 20-25% cooler (making it act more like a 4-5 watt bulb) than if no fan at all. There really is no mystery to these things. If it were me, I would check the temp of the base of the lamp with fan off ( after first leaving the bulb on for 45 minutes) and then check it again with fan on (again after 45 minutes).I assume with you arangement it is easy for you to confirm that with the fan on, there is at least a small "breeze" across the bulb. You may not have any instrument to check temp precisely but let me say that the human finger can stay on anything up to about 45 C, If you can't hold you finger on it, it is over 45-50C. If you can hold you finger on the body of the lamp for a few seconds, it is absolutely running safely. If you can't, it still likely is OK with fan on.
  • 10.30.2013
  • That 60W-equivalent LED: What you don’t know, and what no one will tell you…
  • lightalog--- no the situation has not changed one bit. If you put an led bulb having more 8-9 watts (not watts "equivalency) base up --or even base down, in a fairly tight enclosed fixture you will severely compromise bulb life expectancey becassue the air will becne tgemp elevated inside and the bulb will not be ableto properly cool. If you put base up in a NON enclosed fixtrure, the situation is much better, especially now that bulbs are getting more and more effiecient and needing fewer watts for same lumens. If you go to Lowes, you will see a number of 3-4 watt ( approx 300 lumen) candelabra base (E12) bulbs. under their housebrand Utilitech label, My son has had a half dozen of them operating just fine base up in a chandelier for over a year, and another half dozen base down, in another fixture--Both with high usage. At only about 3 watts, base up in open air is not a big deal at all-- minimal extra heating of the power supply inside. My opinion is that you would have a non problem using these lamps.So with all these LED comments, we have to be sure we donot generalize too much,. If you use lousy bulbs in an ill advised application-yes a problem.If you use right, 2014 vintage bulbs in an informed way in right application you will be just fine
  • 10.30.2013
  • That 60W-equivalent LED: What you don’t know, and what no one will tell you…
  • Tarbert99 You ar so correct-- after seeing a "zillon commetns in repsonse to my orginal poice, let me maqkea final comment. Thre has been "profound" change in the arket dynamics foa 40-60 watt LED equivalent types in last 5 years.. The days of the Chinese markters seeling non ul approved, poorly specified, questonably performing bulbs is pretty much over unless one is living in a cave and buys something online and has no clue as to recent developmetns in technology and price. Today, Philips and Cree have the "default" best products on the market, legitimately specified, priced from $5-9 (depending on whether utility rebates in your area, are fully dimmable, have legit warm white or daylight" designations ,are UL approved and have intelligently designed thermal management. There is a second tier of companies, LG, TCP, Feit etc who now offer comparably priced, comparably designed bulbs. It should be recognized that 100% of all LED bulbs are produced in China--but not all are "designed" or warraned by those "faceless" China companies. Hence I woud only buy frm a cmpany with US engineering and presence of some kind I replaced all my kitchen recessed floodlights(originally incandescent halogen and then the irritatingly-slow-to-warm-up CFL refflector types--but now use Feit LED par 30 types which I bought for $5. Instant on.Feit imports form China like everybody, soetines is a littlke flaky-- hardly a Phlips reputaton but at least i know who they are as a US marketer so I felt on balance their product OK (since I know how to assess. But my pount of all this is that the dust is settling. You can now get a legit 60 watt, instant on, dimmable LEDE bulb from a very legoit supplier for $5-6.
  • 10.30.2013
  • That 60W-equivalent LED: What you don’t know, and what no one will tell you…
  • Bret--- Efficiency and heat are two different things. A 60 watt incandescnt lamp i svery inefficient and gives off a tremendous amount of heat--put under a small metal plate and it willheat you dinner.Its fi,amnent gets to THOUSANDS OF DEGREES but doe not blow out because it is mad eof Tungsten.The outer glass gets extremely hot but nowhere as hot as the light emitting filament inside. The led equivalent gives off same light but only with about 10 watts but that wattage shows up as heat in the bulb housing so you feel it--but it is still only a fraction of the heat in a 60 watt filament bulb-just that you are protected frm touching the filament by the glass outer shell. Your flashlight doesn't have anywhere near the attage or light output of the led bulb--probably only a watt or two. It does not give off more light--just seems that way.The flashlight hasa reflctor which focuses tghe emitted light into a bright spot or circle and when you look at flashlight it seem "super bright" Ther eisa differnce between light "intensity" as see by a viewer and the total light output. If you took off the reflrcto form a flasjhlight it woud only light up the room a fraction of the led bulb.Simiallry if you put the proper reflector over an l3ed bulb it woud be a dramtically brighter "flashlight" The flash light has much less light but al of it is put in one spot so "seems' brighter.Becasu erhe flasghlight is such lower power, it of course has way less heat, many led flashlights have less than a watt of heat even thougth they can project a very bright "spot"on the wall. No mystery here but there is a little bit of science.You question is common "If LEDs are so darn efficient ,why do they get hot?"--only because what little heat exists is right there for you to touch. A paper match does not give off much heat at all --- a super tiny fraction of the heat of a regular light bulb--but it sure would burn your finger to a crisp.I hope this helps.