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  1. KrisBlueNZ

    Proper Usage of Oscilloscope (40 Marks)

    Yes, I would say so. Yes, either way. Yes you could try that. I would increase the time/div until the AC becomes a big thick blur, and estimate the centre of the blur. Edit: This is only valid if the AC component has an equal enclosed area above and below the centre line. Any symmetrical...
  2. KrisBlueNZ

    Transformer problems

    Hmm, that's interesting. I wouldn't have expected a problem. You could use an isolated DC-to-DC converter module e.g. http://www.digikey.com/product-detail/en/JCH1024S05/1470-1971-5-ND/4488351 LOL :-)
  3. KrisBlueNZ

    Capacitive Reactance Circuit

    A switching power supply's efficiency is normally specified at or near full load. It will be lower at lower output currents. This is partly because the SMPS has a fixed power overhead for its internal operation, which becomes a greater proportion of the total power consumption as the output...
  4. KrisBlueNZ

    Impact of surrounding logic - causes

    I suggest you email Xilinx applications support.
  5. KrisBlueNZ

    555 timer question

    The 555 does not restart its time period if another trigger pulse is received while a pulse is in progress. You need to ensure that the trigger pulse (low pulse on pin 2) is shorter than the monostable's period. If pin 2 is still low when the monostable delay expires, this will prevent the...
  6. KrisBlueNZ

    Current limiting strategies for L298N?...

    Sounds like you're being a bit hard on yourself. You seem pretty smart - assembly language programming is not for the faint of head, and your written English is very good. You even know how to use semicolons and colons. You sound a bit like me really! I'd like to have a chat sometime. I'll take...
  7. KrisBlueNZ

    stk500 error entering programming mode

    Have you read all the relevant threads at avrfreaks.net? http://www.avrfreaks.net/search/site/stk500%20error%20entering%20programming%20mode
  8. KrisBlueNZ

    stk500 error entering programming mode

    I suggest you start by typing that error message into Google and seeing what other people have suggested.
  9. KrisBlueNZ

    Transformer problems

    D'oh! Brain failure. Of course you could do what you suggest.
  10. KrisBlueNZ

    Transformer problems

    Nice idea Hop but you can't connect centre-tapped secondaries in series!
  11. KrisBlueNZ

    Transformer problems

    No! But show us the schematic of the amplifier. You can probably replace the rectifier toob with a bridge rectifier made from diodes, and you'll only need a transformer with a secondary voltage of around 370V.
  12. KrisBlueNZ

    Proper Usage of Oscilloscope (40 Marks)

    That's right. And at 10 µs per division, a cycle (20 µs) will occupy two divisions, so there will be five cycles displayed on the whole screen. BTW, the SI unit for seconds is a lower case 's', not a capital 'S'. You will see people writing "µS", "mS" etc all over the place - even experienced...
  13. KrisBlueNZ

    Fireflies blinking lights

    That's an interesting idea. It might make the encapsulation process a bit more difficult. Or perhaps half of the toroid could protrude out the end of the firefly, with the secondary (to power the circuitry) wound around the part of the toroid that's inside the potting resin. Does ferrite rust? I...
  14. KrisBlueNZ

    Designing a Time Delayed Relay

    Wow! That's great!
  15. KrisBlueNZ

    Proper Usage of Oscilloscope (40 Marks)

    To quote a post, click Reply at the bottom right corner of the post you want to reply to. The whole original post will be quoted, with around it. Now if you want to reply to the quoted message in sections, delete parts of it that you don't want to quote, and when you find a place where you...
  16. KrisBlueNZ

    Designing a Time Delayed Relay

    Sure, that would be fine.
  17. KrisBlueNZ

    Proper Usage of Oscilloscope (40 Marks)

    As Dave pointed out, it's the time/div control that you're talking about here, not volts/div. Not quite. The AC signal has an amplitude of 100 mV peak to peak. This means there is 100 mV between the highest peaks and the lowest valleys, and if it's a sinewave, the mean voltage is half way...
  18. KrisBlueNZ

    Phase voltage circuit help

    Could you use some small transformers for isolation?
  19. KrisBlueNZ

    10X20 bar led, to pushbutton

    Hi Devon and welcome to Electronics Point :-) I don't understand what you mean. Can you translate your mental picture into a picture on paper, then take a photo and upload it? Can you tell us the part numbers of any components you already have, so we can check out the data sheets for them?
  20. KrisBlueNZ

    Stage Line 500W amp repair project

    BTW, I don't know if you're worried that you won't be able to understand this stuff, but if you are, don't be. You're a mechanically minded person, and quantities in electronics work in very similar ways; they're just harder to see! (That's why we have oscilloscopes - the second most important...
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