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EdwardM

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Everything posted by EdwardM

  1. Hi Alun Am I missing something, the output is pulsed DC...? are we at cross purposes? Ed
  2. Hi All hopefully to make it clear... Ed
  3. Hi LegendBreath I'm afraid my Vic has gently rusted out in the garage, maybe there's some way of recycling it as a doorstop, ah! technology moves on, in an odd sort of way I'd be happier playing with my Vic, PET, Dragon, Atari or Sinclair (Yes, i've still got them all) than Visual Studio .NET but I have to eat Ed
  4. Hi LegendBreath this takes me back a bit.. but according to websearch Yes, they are identical. The 6507 package was created strictly to save space on the PCB, in those days it did not make sense to create a new die and mask for such an "improvement" since this was much more expensive than the package design. The 6507 in a 2600 should react the same way to undocumented opcodes as the 6502 in a C64. Does that help? Ed
  5. Hi Alun * Absolutely * ;) Ed
  6. Hi scuba14c pulsed DC usually refers to switching on and off the primary of a transformer which is supplied by a DC voltage such that when there is a change of current (switch on or off) that rate of change of current becomes available at the secondary. The secondary is electrically separated from the primary and the on/off action induces a voltage which alternates, it's not a sine wave however, it's nearer a triangle wave. No need, use diodes to rectify the AC waveform to DC. This is the $64,000 question, the answer is that the amount of energy that you put into the primary circuit will be what you can expect from the secondary less any losses. ie you can't get out more than you put in! Suppose that the most power that you can extract from a battery is 1 Watt (purely ficticious and just for argument) and the battery has a voltage of 10v, here I=P/V = 100mA. This means that if you apply this voltage and current to a perfect DC-DC converter you would be able to get the same power out, because you have a transformer you can increase the output voltage as much as you like. Suppose you wanted 1000v output, no problem, but the energy balance has to be maintained and you'll find that 100 times more voltage means that you have 100 times less current available. Look at the Joules per second level and suddenly it gets clearer Best of Luck Ed
  7. Hi scuba14c I posted you some days ago but in looking back over it I didn't include the correct link, have a look at the application note, you will find that it is relevant Best of Luck Ed AN19.pdf
  8. Hi Junaid I'm trying to understand why all of the outputs are high - with input short circuited, after applying HBEN or LBEN do any of the outputs go low ever? You may may need to split the circuit so that only the ICL7109 is operational, ie, remove digit outputs from the bus and ensure that the 7109 works OK on its own. Ed
  9. Hi audioguru afraid I'm only slightly sideways - am Jock but live in south of England 8) Ed
  10. Hi Junaid before going any further, if you haven't already done so, please join the analogue input to GND (ie don't apply any input voltage), this should give a reading of 0000 Ed
  11. Hi Juaid the only thing I can see is that you've left pin 17 floating, in its low state all outputs would be set to 1, it's therefore worth tying this input high. Ed I'll try to answer the other questions shortly...
  12. Hi Junaid it is a convention on the internet that when someone writes with bold lettering it means that he or she is SHOUTING and as you're probably aware most of us react to shouter by ignoring them. You are perfectly free to carry on using bold, no-one will stop you but it severely reduces the chance of having your problems solved. Ed
  13. Hi Junaid no need to use BOLD, can use post a circuit diagram Ed
  14. Hi audioguru maybe we could take the temperature differential between Canada and Oz as the input for a slightly larger Stirling engine 8) Coz last time I was in Canada my eyeballs froze (Belle Isle Strait, December) and every time in Oz, even the occasional rain was warm ;D Ed
  15. Hi Dazza It's an allusion to a game where two teams of hefty blokes pull in opposite directions on a rope, the winner being the team which pulls the other team beyond a set position. :D I was thinking of something like a galvanometer/meter or something where it would be immediately clear which team (Stirling v Photocell) was winning and by how much Ed
  16. Hi Dazza from the web searches I've done on the Stirling engine, it looks like it's the bees knees and someday might even replace the current internal combustion engine :o You could try starting with a very very small motor acting as a generator and use it to light a LED, whilst not very inspiring it will give you an idea of how much power you are actually generating from your temperature difference, you could then set up a solar cell as a comparison (I'm thinking of a tug-o-war) and experiment with different heat sources to find out the best way of driving the beast and then see if it can be scaled up/down and maintain efficiency. Hope this helps Ed
  17. Hi again magatru these PSU's are excellent and have huge current capability but I believe there is a minimum current that needs to be taken from them in order for them to work. What that current is I don't know but I suspect it's fairly low, you'll need a web search on this one and for the on/off switch wiring unless someone on the board knows the answer already ??? Best of Luck Ed
  18. Hi fotoobscura there have been a lot of interesting suggestions arising out of your post, as a finalish one can I suggest that you try to get your local university EE department interested, because of the range of research/disciplines involved I'd have thought they'd jump at the chance, even though I recognise that time is fairly short. Another possibility is to invite an electronics/similar company to participate - lots of praise and honour for them. Best of Luck Ed Audioguru, agree high cost but no soldering/electronics, just fit/forget, current consumption will be high - there are always trade-offs involved :'( Ed
  19. Hi Alun, guesstimating the distances involved from fotoobscura's original post, I'd think the min order qty wouldn't be a problem. ebay sounds good afterwards ;D Ed
  20. Hi tvdbon one way is to connect the 12v supply, a resistor and the LDR, and use the voltage developed across the LDR as the analogue input. You should be able to find an datasheet/application note on the web and from that derive the necessary resistor value. Best of Luck Ed
  21. Hi All, hate to labour the point but I will ;D http://www.titoma.com.tw/energy_saving_light_bulbs.shtml , one example of many, the link describes a small 12v fl bulb, whilst I doubt that it would fit within the size/power/illumination constraints, I'm not sure that the other possibilities will either, roll out the flood lights. Btw, I can remember being hyper impressed some years ago when I first came across fl light as car interior illumination, knocked everything else into a cocked hat. 8) Ed
  22. Good thinking audioguru, sounds about right ;D Ed
  23. Stand-up all those who've never heard of small fluorescent bulbs, shame on you ;D Imagine a regular bulb, about 3 ft long, now scale it down to about 4 inches, these are sold as backlights, interior illumination for cars and as part of some flashlights and for other purposes. Ed
  24. Hi again fotoobscura having thought a bit longer about it, this may seem a bit obscure, but I'd be tempted to look at this from the other direction and that's to work out the light level needed at the artwork to illuminate it as required taking into account any sky illumination, street lights and building lights - this also depends on the reflectivity of the artwork itself. If you can get to a figure for illumination/contrast required then you should be able to work backwards over distance x and work out the distributed source illumination which will finally give you a light density requirement and thus the type of lighting available to satisfy it. As I said, a bit obscure Best of Luck Ed
  25. Hi prateeksikka I've seen the same things in several countries but never in the UK, I've always though that they were there to scare birds or pilots ;D Ed
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