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Why is the light not lighting up? — Parallax Forums

Why is the light not lighting up?

noobmunchernoobmuncher Posts: 124
edited 2009-11-26 06:22 in Propeller 1
Hello,

So i have all the components I need and I have built the circuit from the Propeller Labs, however I am running into a problem right off the bat. The led is not lighting up. I have tested everything that the trouble shooting area says to and I am kind of confused. The main thing that I find odd is that across the LED i am only getting 0.12 volts across when old the Prop plug is powering it, yet when i power it with only the 9volt I still only get 0.13 volts. The 9 volt is new and i just tested it, the wiring all seems to be correct ( i have checked and rechecked it) the resister running to the LED is 100 oms 1/4W 5% (brown black brown gold), I have tested several LEDs all of which I have tested on my other boards, both capacitators are 1000 uF 6.3V and the voltage regulators are 5 volts and 3 volts. I have tested it with the led connected without the resistor and i still don't get any light, in fact i only get 0.15 volts.

Any idea what I am doing wrong?

Thanks for any help, problems with circuits are always so frustrating to work with.

Comments

  • Toby SeckshundToby Seckshund Posts: 2,027
    edited 2009-11-25 21:53
    Without any cct for clues, You haven't fallen for the Pin1 is P0 ... trap have you?

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Style and grace : Nil point
  • sylvie369sylvie369 Posts: 1,622
    edited 2009-11-25 22:37
    noobmuncher said...
    Hello,

    So i have all the components I need and I have built the circuit from the Propeller Labs, however I am running into a problem right off the bat. The led is not lighting up. I have tested everything that the trouble shooting area says to and I am kind of confused. The main thing that I find odd is that across the LED i am only getting 0.12 volts across when old the Prop plug is powering it, yet when i power it with only the 9volt I still only get 0.13 volts. The 9 volt is new and i just tested it, the wiring all seems to be correct ( i have checked and rechecked it) the resister running to the LED is 100 oms 1/4W 5% (brown black brown gold), I have tested several LEDs all of which I have tested on my other boards, both capacitators are 1000 uF 6.3V and the voltage regulators are 5 volts and 3 volts. I have tested it with the led connected without the resistor and i still don't get any light, in fact i only get 0.15 volts.
    I assume from your talk about the capacitors and the like that you have built the power supply from the circuit in the Prop lab. Did you have a chance to test that to make certain that·you're getting 3.3V and 5V from the appropriate places? It sounds like you have a multimeter, so it'd be a good place to start to make sure that your power supply is working.

    If that's okay, then you should try just wiring the LED/resistor from 5V to ground to get it to light that way. Be sure to keep your connections away from the Prop pins! In fact you might want to remove the Prop chip while you're testing things in general.
  • noobmunchernoobmuncher Posts: 124
    edited 2009-11-25 23:01
    Okay thanks I will try testing out the supplies when I get home in under an hour and I will let you know. AS well, i don't think I have messed up the pins because I have copied EXACTLY off the picture.
  • noobmunchernoobmuncher Posts: 124
    edited 2009-11-26 00:40
    Well I have narrowed it down through building my own separate circuits, is it possible that it is because my 9 volt is only 8.5 volts now? Although i have a feeling its because of my voltage regulators because even when it is just that, a battery, a capacitor and a LED and it is STILL not lighting up. Once again I have been checking with my multimeter and still getting below 1 volt. As well I have been checking to make sure my LED is not burnt out or something like that.
  • StefanL38StefanL38 Posts: 2,292
    edited 2009-11-26 06:22
    which propeller-kit are you using ? (Parallax-order-number)

    about WHICH LED are you talking ?

    The one connected to the powersupply like in the schematic in the attached picture ?

    From this schematic you can see that it operates properly from 6V to 9V so 8.5V should work.

    If you check the voltages between GND and the 5V-point what voltage do you have ?

    If you check the voltages between GND and the 3.3V-point what voltage do you have ?

    What EXACTLY did you narrow down ? Does the separate circuit work as expected ?
    Do you get the 5V and the 3.3V with the separate circuit ?

    best regards

    Stefan
    PowerSupply.png
    1019 x 377 - 29K
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