Why isn't this circuit working? - Electronic Circuits Projects Diagrams Free

Benji966 · 26th April 2008, 06:12 AM

Hello I am a very, very, very non-electronic person, so I thought I could do a simple task of making a LED circuit, but I guess I was wrong. I am running this off of a 13.8V source, theres 4 blue LEDS (3.2V ea), and I have a 1/8 watt 56 ohm resistor. By all accounts this should light up I suppose but it didn't, the LEDs all were working and I can assume the resistor was as well, but when I hooked it up, nada. I assume the problem lies with my soldering since I am no expert in that area. Any ideas on how to fix this would be great! Thanks!

Pics of my circuit:

http://img509.imageshack.us/img509/4724/elecgu0.jpg
http://img509.imageshack.us/img509/1036/elec2lg2.jpg

House0Fwax · 26th April 2008, 10:53 AM

By the looks of the second picture, absolutely everything is soldered together. That's got to be the biggest solder short I've ever seen.

ericgibbs · 26th April 2008, 11:07 AM

hi benji.
Post the circuit diagram and a photo of the soldered side of the pcb.

shaneshane1 · 26th April 2008, 12:27 PM

Quote:

Originally Posted by Benji966

Hello I am a very, very, very non-electronic person, so I thought I could do a simple task of making a LED circuit, but I guess I was wrong. I am running this off of a 13.8V source, theres 4 blue LEDS (3.2V ea), and I have a 1/8 watt 56 ohm resistor. By all accounts this should light up I suppose but it didn't, the LEDs all were working and I can assume the resistor was as well, but when I hooked it up, nada. I assume the problem lies with my soldering since I am no expert in that area. Any ideas on how to fix this would be great! Thanks!

I would assume you are running them in series at 20mA?

so the four LED's = 256mW!

and the resistor = 20mW!

So i would assume it would work!

make sure that the LED's are in series correctly, meaning that the +(anode) and - (cathode) are not touching together!

john1 · 26th April 2008, 12:39 PM

Yes, it looks like you've soldered all the connections together,
to make one join.

Other than that, the lamps are all the same way round,
and all the parts are in series,
its just that they need to be connected individually,
with a solder join for each junction.

Its not far off correct, just a bit of practice.

Oh, and dont have the copper conductor running along them in a line,
try to have a seperate bit of copper for each join.

Best of luck with it,
John

Benji966 · 27th April 2008, 03:23 AM

Ok so I resoldered everything, the blue lines are the solder, the L+ L- are the LED's. + and - are the source and ground. Still doesnt work. Did I do it wrong again?
http://img169.imageshack.us/img169/2756/ledtr3.jpg

mike50 · 27th April 2008, 05:02 PM

Quote:

Originally Posted by Benji966

Ok so I resoldered everything, the blue lines are the solder, the L+ L- are the LED's. + and - are the source and ground. Still doesnt work. Did I do it wrong again?
http://img169.imageshack.us/img169/2756/ledtr3.jpg

It is not easy to tell exactly what you meant by that picture, but it looks like you have two of the LEDs wired backwards.

Reverse the two LEDs, whose connections I've circled in yellow.

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26th April 2008, 06:12 AM	(permalink)
Benji966	Why isn't this circuit working? Hello I am a very, very, very non-electronic person, so I thought I could do a simple task of making a LED circuit, but I guess I was wrong. I am running this off of a 13.8V source, theres 4 blue LEDS (3.2V ea), and I have a 1/8 watt 56 ohm resistor. By all accounts this should light up I suppose but it didn't, the LEDs all were working and I can assume the resistor was as well, but when I hooked it up, nada. I assume the problem lies with my soldering since I am no expert in that area. Any ideas on how to fix this would be great! Thanks! Pics of my circuit: http://img509.imageshack.us/img509/4724/elecgu0.jpg http://img509.imageshack.us/img509/1036/elec2lg2.jpg

26th April 2008, 10:53 AM	(permalink)
House0Fwax	By the looks of the second picture, absolutely everything is soldered together. That's got to be the biggest solder short I've ever seen.

26th April 2008, 11:07 AM	(permalink)
ericgibbs	hi benji. Post the circuit diagram and a photo of the soldered side of the pcb. __________________ Eric "Good enough is Perfect" PIC tutorials: Gramo's: www.digital-diy.net/ Bill's: www.blueroomelectronics.com/

26th April 2008, 12:39 PM	(permalink)
john1	Yes, it looks like you've soldered all the connections together, to make one join. Other than that, the lamps are all the same way round, and all the parts are in series, its just that they need to be connected individually, with a solder join for each junction. Its not far off correct, just a bit of practice. Oh, and dont have the copper conductor running along them in a line, try to have a seperate bit of copper for each join. Best of luck with it, John __________________ ************************************************ ***************

27th April 2008, 03:23 AM	(permalink)
Benji966	Ok so I resoldered everything, the blue lines are the solder, the L+ L- are the LED's. + and - are the source and ground. Still doesnt work. Did I do it wrong again? http://img169.imageshack.us/img169/2756/ledtr3.jpg