Oliver Sedlacek

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Oliver Sedlacek

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  • 04.25.2017
  • Merging power and data: good, bad, or both?
  • As ever, the devil is in the details. Powering electronics falls entirely in the downside; the users would rather not need it, the manufacturers would rather not pay for it, but it's unavoidable. For low power devices the wide availability of 5V at 0.5A from USB ports is a God send. I've been going around our house and upgrading a selection of mains outlets to mains outlets with USB power connections, and I'm delighted with their convenience. For high power appliances, i.e. more than say 250W, you are going to be plugging them into the mains. Despite some hype, I'm still not convinced of the sanity of the WiFi kettle. It's the middle ground that gets interesting, and the devices I'm thinking of are large tablets (or small TV screens), audio systems and LED lighting. That's not perhaps as many devices as one might initially think.
  • 02.03.2014
  • Simple circuit indicates a low battery
  • There's a big difference in efficiency between red LEDs too. For example the Toshiba TLSH157P outputs around 230 Cd/A compared with 6 Cd/A for an old school HLMP3750
  • 03.22.2017
  • Der alte battery
  • Most battery manufacturers quote a 'self discharge' rate, which will be higher for the larger cells. From memory, this will limit you to something over 7 years, but it means the D cells don't do better than AA cells. I did work on a product where we guaranteed two years operating life off two AA cells and I had to get the average consumption down below 70uA. We had initially estimated the limit at 100uA, but if the batteries got cold (which they did in this application) they lost capacity.
  • 03.10.2017
  • DC Transformer? Forward converter? Isolation amp? You decide!
  • Very thought provoking! My first thought was that in practice the fact that link between the ports breaks down during the switching period, and it is inevitable that at some point a load transient would coincide with a switching event. This could however be easily mitigated in a polyphase implementation. I would be really interested to see that actually tested for transient response!
  • 01.28.2017
  • A slick upgrade to industry-standard RAID
  • It's good to hear stories when technology "Does what it says on the tin". I was put off RAID when an array went down and I lost everything. I learned from that experience that RAID is not immune to common point failures (eg PSU spike taking multiple drives out simultaneously) and the need for a big flashing light to tell you when one drive is down and you need to replace it RIGHT NOW.
  • 10.15.2016
  • A sensible 30A energy meter
  • Another cracking chip from LT. Mind you, it probably makes my recent work on power monitoring completely obsolete.