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  1. KrisBlueNZ

    Easiest thing in the world - Quiz Board Circuit Project

    Hi and welcome to Electronics Point :) You said 6 questions and 6 answers but your "diagrams" only have 5 of each. So you just want a column of buttons, and a column of indicators, with the buttons wired to illuminate the indicators with some predetermined mapping? You've answered your own...
  2. KrisBlueNZ

    0.5 volt signal to earth signal

    No, it's not too difficult. I'll draw something up within the next day or so.
  3. KrisBlueNZ

    12v Powerbox for Camping/fishing

    Fair enough. You're going to be carrying this in a backpack, right? So you want to minimise weight? Have a look at http://en.wikipedia.org/wiki/Rechargeable_battery#Table_of_rechargeable_battery_types. I don't know how up-to-date it is, but it should give you a good idea of which technology to...
  4. KrisBlueNZ

    12v Powerbox for Camping/fishing

    You could also try Googling rechargeable power pack. There are many kinds available.
  5. KrisBlueNZ

    0.5 volt signal to earth signal

    OK, it looks like my guess was wrong. So on the 200 mV range, you see a reading of 002.7 while the hydraulic lifter is running, and it slowly decays to zero when the lifter stops? In that case, it really is just a 0.5V DC signal. Bummer. So there's a +12V rail on pin 6 of that connector? And...
  6. KrisBlueNZ

    Temperature compensating a transistor?

    No, that's not a good idea. The impedance of that point will vary with the frequency of oscillation, so the high and low trigger voltages for the Schmitt will also vary. Another way to put it is that at lower frequencies, the current through the feedback resistor will pull the voltage at the top...
  7. KrisBlueNZ

    Remote Control Circuit with CD4017 - counter decoder

    There is a problem with the connection between the TSOP1738 and the transistor. I will draw up a full schematic for the receiver along with the transmitter. Give me a day or two. Sure you can credit me with the design, of course. Just credit me as KrisBlueNZ.
  8. KrisBlueNZ

    Adding capacitor to DC motor

    I'm not sure what you're asking. You can connect any capacitor across a DC motor. This is always a good idea, to reduce electrical noise. It may also have a small effect on the motor's torque. But it will not change the motor's speed.
  9. KrisBlueNZ

    Use Of Current Source?

    I tried to find a good explanation for a source follower but the ones I found were either too vague or too technical, so I'll explain it myself here. The source follower configuration, also called common drain configuration, is the JFET and MOSFET equivalent of the emitter follower (aka common...
  10. KrisBlueNZ

    capacitor allow dc or ac

    LOL :) It depends on your point of view. "A capacitor passes AC and blocks DC" is the usual way to explain it. If you find any article that says the opposite, please post a link to the article and we can see whether it's simply wrong, or whether it is explaining a capacitor from a different...
  11. KrisBlueNZ

    Temperature compensating a transistor?

    OK, you've fixed one problem, but not the other. You also have not shown the power supply connections to the op-amp. These are important in determining whether the circuit will work. As an aside, your arrangement to generate a half supply voltage on the 4.7 µF capacitor can be simplified and...
  12. KrisBlueNZ

    doubt in active device

    It means that the person who wrote that page doesn't know what he's talking about and/or cannot express himself clearly.
  13. KrisBlueNZ

    0.5 volt signal to earth signal

    Yes, that's the right part. Although it won't look like the picture! I suggest http://www.maplin.co.uk/p/decoupling-ceramic-disc-01uf-capacitor-n43cj or http://www.maplin.co.uk/p/wima-metallised-polyester-pet-63v-01uf-capacitor-n20cn or...
  14. KrisBlueNZ

    Voltage controlled thru opamp playing up?

    It's called "ASCII art". You will see it in many posts on this site and others. It began in the 1980s as a simple and quick way to draw diagrams that were so simple that a proper graphical drawing wasn't worthwhile. It's also easy to quote. It's less common now because text is normally displayed...
  15. KrisBlueNZ

    preamp

    What "signal" do you want to amplify? You know that you can't "amplify" a 9V battery to produce 10,000 volts, don't you?
  16. KrisBlueNZ

    single power supply + communictaion

    It's difficult to say what the problem is. A proper, complete schematic and a code listing might help. The 555 circuit will cause noise on the power supply rail. It would be a good idea to try powering it from a separate supply of the same voltage that the microcontroller is using. Connect...
  17. KrisBlueNZ

    Remote Control Circuit with CD4017 - counter decoder

    The decoupling capacitor should be connected between those pins. One wire from the capacitor to pin 16, the other wire to pin 8. Keep the wires as short and direct as possible. You won't find a 38 kHz ceramic resonator. They have frequencies from a few hundred kHz up to a few MHz. You use the...
  18. KrisBlueNZ

    Temperature compensating a transistor?

    Hello and welcome to Electronics Point :-) I also don't see how that circuit will work. I think there's a resistor missing between the non-inverting input and the 0V rail. What are the power supply rails? They should be shown on the diagram. The transistor won't do what you expect if it's...
  19. KrisBlueNZ

    Remote Control Circuit with CD4017 - counter decoder

    A decoupling capacitor is just a capacitor that's connected between the VDD and VSS pins (pins 16 and 8 on a CD4017) as close to the IC as possible and with leads as short as possible. Typically a 0.1 µF ceramic capacitor is used. It is highly recommended for logic devices, especially MSI ones...
  20. KrisBlueNZ

    0.5 volt signal to earth signal

    Yes, Spiratronics looks good. Good information on their web site. Yes you could get a LS4N46 optocoupler. I had a feeling you were in the U.K. Tractors bring to mind Farmer Palmer - "Get orfff moy laaaand" :-) I'm glad to see duke37 on this thread. He'll sort it out!
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