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  1. Hero999

    LM335 showing incorrect value?

    When you get round to improving it, try the AD780 which gives 3V or 2.5V
  2. Hero999

    LM335 showing incorrect value?

    I had a feeling you'd done that. Have you measured the power supply voltage? Bear in mind that most regulator ICs such as the LM7805 have a poor voltage tolerance and will vary by 1% or so depending on the ambient temperature and load current. If the supply voltage is too low, the ADC will...
  3. Hero999

    Some articles

    Yes, fluorescent blacklights will work but are nowhere near as powerful as high pressure mercury vapour lamps. To be honest, I think high pressure mercury vapour lamps are overkill, fluoroscent blacklights should be more than powerful enough. That doesn't make any sense, a colour temperature and...
  4. Hero999

    Some articles

    I haven't seen the original article. Here's my guess at the meaning, going from the poorly worded paragraph you've quoted. The project uses high pressure mercury vapour lamps which take five minutes to warm up and produce full light output.. This is because the light producing discharge...
  5. Hero999

    LM335 showing incorrect value?

    I don't know much about MCUs, especially C so I can't help you with the coding. I don't it's a coding problem, it's more likely to be a hardware problem. Where does the ADC get its reference from? I'd recommend checking that before anything else.
  6. Hero999

    LM335 showing incorrect value?

    Good, you found out what the problem was. It's just really back luck that both your DVM and ADC are wrong.
  7. Hero999

    LM335 showing incorrect value?

    How well water proofed is the sensor? Could it be that moisture is getting in?
  8. Hero999

    Re: made my first PCB --- but there are questions :p

    That's lucky it worked for you but some mercury lamps stop working if the shield is damaged or removed.
  9. Hero999

    LM335 showing incorrect value?

    What is your room temperature? You still haven't said. How did you measure it? There's no point in calibrating it unless you accurately measure the temperature of your room.
  10. Hero999

    LM335 showing incorrect value?

    I don't know what you could be doing wrong. Obviously you need to know the exact temperature of the LM335Z to know it's working correctly. My guess is that it's working and the temperature of the LM335 is pretty close to 40
  11. Hero999

    LM335 showing incorrect value?

    A quick look at the datasheet tells me that the voltage shouldn't vary much as the current changes so the resistor value won't make any difference - I was wrong earlier. Does the voltage increase when the temperature sensor is warmed? Have you had your multimeter and thermometer calibrated...
  12. Hero999

    anyone have any Light circuit

  13. Hero999

    Re: made my first PCB --- but there are questions :p

    Some photo papers are wax coated or actually plastic and are water resistant, did you try normal copier paper? I know I said use the highest heat setting but I've changed my mind since then, lower heat settings seem to be better because the toner doesn't smear so much. That's right, it doesn't...
  14. Hero999

    IR Audio Receiver

    There is nothing wrong with using emitter followers since current gain is required, not voltage gain. The circuit won't work anyway because IR remote controls flash the LED at an ultrasonic frequency so you won't be able to hear it. I would recommend using an LED to indicate the output, a tone...
  15. Hero999

    LM335 showing incorrect value?

    I can't read your rough ASCII schematic, please post a clear drawing in either.GIF or .PNG format, avoid .JPG which can be fuzzy. Look at the datasheet for more information on how to use the LM335. Use ≤1% tolerance resistors - 5% won't be accurate enough. http://www.national.com/ds/LM/LM135.pdf
  16. Hero999

    Re: sensor circuit

    The absolute maximum voltage rating is 7V so you'll probably get away with it but it isn't recommended. The trouble is the battery voltage will drop below the minimum voltage rating before the the cells fully discharged. Why are you using an old power hungry TTL lC? You should use a low...
  17. Hero999

    Re: 600 WATTS LM4702 POWER AMP

    I've never understood why people incorrectly copy circuits from datasheets and pretend they designed them when it makes it obvious that they don't know how it works.
  18. Hero999

    Re: sensor circuit

    Why do you need to simulate it? There shouldn't be any need to because the circuit is so simple, just use Boolean algebra to work out what will happen. Even if you simulate it and it works it doesn't mean it'll work in real life. The simulation program doesn't know the ambient lighting...
  19. Hero999

    Help

    No one's going to do your work for you. If you make an attempt at solving the problem then we might be able to assist you.
  20. Hero999

    buying parts on line

    I already responded in the other thread. Please don't create multiple threads asking the same question. http://www.electronics-lab.com/forum/index.php?topic=19195.msg88251;topicseen#msg88251
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