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  1. chopnhack

    USB Chargers

    Thanks Kris! A lot of thought went into the development of that specification with lots of exception handling capabilities.
  2. chopnhack

    USB Chargers

    That is an interesting thought Bob and quite possible!
  3. chopnhack

    USB Chargers

    Understood :-) It's a shame that there is a standard for USB, but then there are so many different "proprietary" charging schemes. Great way to sell accessories, but not so great for interoperability!
  4. chopnhack

    Bench Power Supply

    Aside from the above questions, what would be the advantages of a dual tracking supply?
  5. chopnhack

    USB Chargers

    This is a product from a very large electrical supplier (Leviton), do you think its just marketing lingo or is it a good product? This is from the spec sheet: 4-Port USB Charger, 4.2 AMP, 2.1A Max per output Microprocessor and smart chip designed for recognizing and optimizing the charging...
  6. chopnhack

    USB Chargers

    I think I found a great candidate for a hack: http://www.leviton.com/OA_HTML/ProductDetail.jsp?partnumber=USB4P-W&section=63493&minisite=10251 A four port usb charger with a built in microprocessor claiming to boost recharge speed. I assume that the manufacturer pre-programmed the micro with...
  7. chopnhack

    USB Chargers

    Ah, thanks for clarifying. The intent was to make a piece of functional equipment that would incorporate the USB charger in it. As such, it would need to be powered by mains. Hacking a manufactured unit for the "guts" is the best option at this point.
  8. chopnhack

    Trophy points implementation?

    You guys, Steve, Harald and Arouse1973 all get trophies in my book - the help and guidance has been immeasurable. Also, the resources section is really becoming top notch. Steve's post on heatsink is exceptional - illustrated well. Keep posting, I may one day learn what all these parts do...
  9. chopnhack

    Survey about a PCB to schematic conversion app? (10 seconds)

    Survey taken! Excellent idea - devil in the details to get it to be spot on, but wonderful concept. I would imagine that a lot of guess work would be incumbent on the end user when it comes to unlabelled ic's, but it would be a great tool and would save some time in creating a schematic from...
  10. chopnhack

    Noob question about my resistor problem

    Seems correct if you place the two resistors in parallel, the net resistance would still be roughly 100 ohms and you could dissipate more heat via the two resistor bodies. Are these LED's going to be lit intermittently or continuously? That is where the dissipative characteristics of the...
  11. chopnhack

    USB Chargers

    Care to elaborate further?
  12. chopnhack

    USB Chargers

    Yes, I had read reference to that event on the web... very sad and for probably a few cents worth of circuitry...
  13. chopnhack

    USB Chargers

    LOL, that is a funny article.!
  14. chopnhack

    USB Chargers

    Thanks Kris, I found this article interesting, but at over 2 years, I figured things may have changed: http://www.eetimes.com/document.asp?doc_id=1279469 I found some inexpensive units at around $14 for 4 ports, but I doubt the quality.
  15. chopnhack

    USB Chargers

    Does anyone have a source for relatively inexpensive but decent quality USB chargers? Is it cheaper to make them in small scale than it is to buy them ready made? I am looking for a module that would plug into mains power and charge up to four devices. Thanks for any assistance.
  16. chopnhack

    Designing a Time Delayed Relay

    This is a mental note for myself to keep a tab of where I left off on this project: Redraw schematic, change 78L05 to SMT component with heat sink pad top layer, build new components in eagle, layout pcb, new BOM.
  17. chopnhack

    Isolation Transformer Potential to Earth Ground

    It seems that the consensus from the article is that its useful to sometimes have complete isolation including no ground on the isolation side - just a floating loop and at other times its useful to have the grounds tied together. A little ahead of my experience at the moment, I hope when I get...
  18. chopnhack

    Scrap Tinkering

    I got tired of reading theory, learning CAD programs and programming languages! I thought a little hands on tinkering would be nice for a change :-) I salvaged some LED's from a scrapped wifi board and a pcb from a kids nightlight that failed. I wanted to see if I could hook up some LED's in...
  19. chopnhack

    Isolation Transformer Potential to Earth Ground

    Gold star, mate - that really clarifies it for me, thanks! Ground is common, so how is the ground pin grounded in your isolated output socket?
  20. chopnhack

    Isolation Transformer Potential to Earth Ground

    I am somewhat confused by the schematic below. On the isolation side of the transformer, the hot lead is shown as having a 0 V potential to earth ground? If I was to probe the hot lead to earth ground I would have no potential?? Can someone clarify this for me, I can kind of see how this could...
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