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Everything posted by PeterG

  1. Hi all, I need your help. What hfe should the BC548 (or BC547) and the BC557 (or BC327) have? A search in this thread didn't turn up any hits, which I find surprising. Hasn't anyone else wondered whether a BC548A, BC548B or BC548C is the right one? Or doesn't that matter? Thanks, Peter
  2. Dang. I've written quite a lengthy reply, but when I clicked on send, the forum said I wasn't logged in and my posting was gone. Never click on send before pressing Ctrl+A, Ctrl+C. I should've learned that by now. :( I'll repeat the most important part only: -------------------- Thanks for your reply, MP. Is there a difference between the corrected schematic (posted my Mixos) and the PCB layout on the project page? I haven't checked that yet. I've relied on the assumption that when there's an updated schematic posted, a faulty layout would not remain on the project page. Should I have designed my own PCB layout, referring to the updated schematic? (Actually, I have designed my own layout, but I've referred to the layout on the project page.)
  3. Hi all, I've just finished my DVM (with 7805/7905 power supply) and for a minute, it worked well (zero reading with no input voltage, correct reading with input voltage). Good! :) Then I've fiddled around with the wires and, for some reason beyond me, the DVM ceased to work. Now it keeps showing a crippled (but bright) 3 on the first digit (a 3 without the upper and lower bar). When I switch the DVM off and on again, the 2nd, 3rd and 4th digit show a (seemingly random) value for a split second and then the funny sign on the 1st digit comes back. Bad! :'( I've re-soldered anything. Didn't help (as expected). Anyone has a hint on what to do? It'd be appreciated. Peter
  4. How come that Sensirion is in that list? They sell expensive sensors only of which you can't order samples. Would be too nice to be true.
  5. Hi. I'd point a bright focused flash light to the sensor and see if it shuts the light off. If it does, the sensor isn't UV-only-sensitive (and I don't think it is). Of course, you'd still have to figure out how to trigger the sensor on an every night basis. But are you sure that you can take the responsibility of shutting a street light off? If there's really no point in having that street light burn all night (which costs your city money), have you considered talking to your municipality (or whetever)? P.
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