whats going on?

• Jan 20, 2008

• #1

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bcroft

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i have been reading and reading these forums for over a month now.  finally got all the right parts, made a driver, tested it with 4 LEDs and its good.  got my diode put the silicone and capacitor on it, hooked it up to my driver.  popped in 2 AAs flipped the switch and nothing!  adjusted the pot and still nothing!  does anyone have any ideas what i did wrong?  i used 2-10 Ohm resistors, LM317T, 1N4001 and 47uF 16V.  i read more and used a 47uF 35V, still nothing.  VERY frustrating and dissapointing!

Hate being a noob!

 

• Jan 20, 2008

• #2

Gazoo

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You need to supply at least 6 volts to the driver. Use 6 AA or AAA batteries. The capacitor has nothing to do with the output...all it does is absorb voltage spikes.

 

• Jan 20, 2008

• #3

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bcroft

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not enough power ehh.......THANKS!

 

• Jan 20, 2008

• #4

FireMyLaser

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To be safe, test with the LEDs again when ur done.

 

• Jan 20, 2008

• #5

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bcroft

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Thanks, i just got done testing it. my LED is really bright through my switch, pot and up to my LM317 (Vin). It dims to about half its brightness at my LM317 (Vout). It barely lights at my LM317 (Adj), i follow that to my 2-10 Ohm resistors and where my resistors connect with my 1N4001&Capacitor my LED does not light. I used 6 AAs. im still??? you think my LM317 is bad, or my resisotrs?

 

• Jan 20, 2008

• #6

FireMyLaser

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Are you sure that all your connections are correct? How many mA?

 

• Jan 20, 2008

• #7

rog8811

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Thanks, i just got done testing it

Click to expand...

Is that with a multimeter? Testing with an LED will only tell you that there is some voltage at some current.........
First things first, you need to measure the voltage between out and adjust on the LM317, you should get 1.25 v.....that will tell you that your regulator has enough volts and is trying to do its job.....any other reading and something is wrong.

Regards rog8811

 

• Jan 21, 2008

• #8

Hemlock_Mike

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When you originally tested the driver with 4 LED's, what was your power source and current then ??

Mike

 

• Jan 21, 2008

• #9

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bcroft

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regretably i dont have multimeter. i used a LED just to get a guess where my problem is at. i just used 2 AAs on my breadboard when i tested it with 3 LEDs. i said i used 4 earlier, that shoulda been 3, sorry