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Analogvideo

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About Analogvideo

  • Rank
    Distinguished Member
  • Birthday 05/19/1957

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  • Website URL
    www.stonard.com

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  • Location
    Campbell, California, USA
  • Interests
    Collecting: Radio Tubes/Valves; Broadcast TV gear. Electronics Hobbyist
  • Occupation
    Marketeer
  1. csmith wrote: Chuck et al., I've been using those "red top bins" (The 12 Gallon Tuff Crates made by Contico) for some years. This topic is timely as yesterday I visited the local Home Despot for a few more crates. None to be found! To cut a long story short, the vendor, Contico a division of Katy Industries, stopped shipping these to Costco or to HD due tocancelled orders. The nice lady at Contico thought that HD would again order, and suggested I keep an eye out for them. The folks at HD HQ were unable (or unwilling) to answer my email beyond cut-n-paste appologetic fluff. Mostl
  2. nashbar wrote: Nashbar, Yes, a series string of ten car batteries. (Note that a fully charged twelve volt car battery produces 13.8V, or 138V for all ten, so you'll only needeight to get 110.4V). What energy level do you need (measured in watt-hours)? A smaller amount could be obtained from eighty-eight series connected NiCad AA batteries (88 * 1.25V = 110V) or thirty Lithium Ion cells (30 * 3.7V = 111V). What are you operating from this power source? Batteries only produce DC, so electric motors and "computer controlled" holiday lights will not work. Why is your question
  3. Rachel Herron wrote: Rachel, I'm enjoying your project thread! Now that you've touched on electricity costs, perhaps you'd like to see this thread (if you haven't already found the data): http://planetchristmas.mywowbb.com/forum13/776-1.html I did a bit of digging to discover there's a wide range in electricity costs, and some of us are on a tier system that makes the 'last kilowatt-hour' twice the cost of the 'first kilowatt-hour' each month. Ouch! Comments Welcome!
  4. hmfic wrote: hnfic, This is not true. The European and US electric utility industries developed about the same time at the end of the 19th century, and independently. That is why Europe has 50 cycles per second (50Hz) AC power, the USA (and Canada) have 60Hz, and some areas (notably Japan) have both. (Western Japan was populated by US service personnel after WW-II and those areas are 60Hz). South America is also a mix of voltages and both 50 or 60Hz systems. Frequency: The 60Hz standard (USA/Canada) was invented by Nicola Tesla, who concluded it was the most efficient for AC generator
  5. ErnieHorning wrote: Ernie, Thanks for the quick and detailed reply. From your observations I thinkwe cansay that mini-lights with a shunt can be safely used in parallel from low voltage, or in shorter strings (i.e. 12 or 24V), and when the filament fails (which it will eventually) the shunt does not activate unless the applied voltage is much higher. In the intended application the filaments are all in series with a couple of volts across each one. If one fails the open circuit voltage would be 120V (ish) RMS, (161V peak)and all bulbs would go off. With a shunt system the increasing v
  6. toozie21 wrote: Jason, This doesn't sound right either. What was the DC and ripple voltages after the bridge rectifier? What was the load current? A full-wave (bridge) with capacitor filter produces 1.4 times the RMS voltage of the AC input. The output voltage is maintained by the capacitors and recharged by the next AC half-cycle. The bridge rectifier and transformer see high peaks (1.8 times the DC output current) as it powers both the load and the capacitors. Comments Welcome!
  7. toozie21 wrote: Jason, This doesn't sound right either. What was the DC and ripple voltages after the bridge rectifier? What was the load current? A full-wave (bridge) with capacitor filter produces 1.4 times the RMS voltage of the AC input. The output voltage is maintained by the capacitors and recharged by the next AC half-cycle. The bridge rectifier and transformer see high peaks (1.8 times the DC output current) as it powers both the load and the capacitors. Comments Welcome!
  8. ErnieHorning wrote: Ernie, Tell us more about your experiments. I've also played with shunted bulbs, and used them with parallel connected low voltage (and had no problem with unwanted shorting). How did you test the bulbs? Were they good bulbs (destroyed in the experiment) or burned-out bulbs (showing high impedance before the test)? How did you apply and control the rupture current? Was a current-limited supply or other ballast (more bulbs?) used withthe test bulb(s). Were you just curious or were you working on a failure mode or other problem with an existing holiday lights d
  9. toozie21 wrote: Jason, This doesn't sound right to me. If your transformer is rated to 24V AC, how did you end up with a 24V DC output (after the bridge and capacitor(s)? Comments Welcome!
  10. Mvipond wrote: Mvipond, I create PC Boards for some of my electronics projects and I'm familiar with the effort required to complete the design and the approximate cost of tooling prototype PCBs. The production boards are cheaper (more so as the quantity goes up), but a fair price amortizes the cost of development into the first production run. If you'd like to make your own PCBs contact me off list and I'll steer you to low cost fab houses, assuming that you have a way to create CAD files ("Gerbers"). If you’re not using CAD for design these aren’t much help. If you’d like to learn
  11. toozie21 wrote: Jason, Data was lifted from the recent (post-Xmas sales) purchases. "Back in the day" there were more variety of string lengths and bulb specs, even amongst mini-lights. In those days it was important to select the right bulbs (2.5 to 12V IIRC) for a particular string. It's quite likely that you have seen bulbs that draw higher currents. Please post data if you have it. Comments Welcome!
  12. Roadrat wrote: Roadrat, Correct. You're describing a "state machine", and IC memory is a neat way to store the data. The hardware can exist without a uC (or uP), using a clock and counters for the ROM address. This technique was used back in the 1980s to generate complex analog waveforms from stored digital patterns held in ROM.An A2D and anti-aliasing filter provided the output(s). By far the best method for constructing any of these sequenced displays is the uC, it's cheap, reliable, easily changed (In Circuit Programming or Bootloader andcom port) and can be developed in a vari
  13. toozie21 wrote: Jason, Excellent job so far! I look forward to seeing a video (MOV, WAV, etc) when you havethe snow-fight animationup and running! Regarding operating current for mini-lights, check out this thread: http://planetchristmas.mywowbb.com/forum13/2617-1.html Here's the datathat Iposted there: I hope this helps! Comments Welcome!
  14. toozie21 wrote: Jason, Breaker, not fuse. Both breakers and normal fuses allow strong overloads to prevent nuisance tripping, fast-acting fuses do the opposite. The time-delay characteristics of typical breakers was quoted from a graph, which might make more sense to you. Image attached. Comments Welcome!
  15. toozie21 wrote: Jason, I think Roadrat has set you straight. A Triac can be triggered and will conduct until the holding current threshold has been reached - typically at the next zero-crossing of the AC power. Delaying the start does reduce the power in the load, and provides dimming, but it also creates a lot of EMI/RFI unless filter components are added. The high dv/dt can also destroy the Triac, and that's why there is a CR snubber across MT1 and MT2. My scheme skips half cycles to reduce the power to the load. If one of four half cycles are skipped the load is at 75%,
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