LM317T and how it works

[Rleo6965]

I think you missed 1 wire connection . Please see picture with my correction. Connect another wire as shown by Blue Line. You might want to add 10 mfd 16V capacitor for cleaner dc output.

Next time you use better use quality soldering lead so that solder should be glossy not dull. That kind of soldering lead will cause weak mechanical connection. Your installing your pcb on a car that have engine vibration and will cause loose connection or intermittent problem in the future.

 

[c131frdave]

Thanks. I think I'm going to start over. lol I think it is actually wired that way as you illustrated- but I may have put the resistor across 12V and output by mistake... It's hard to see as my eyes no longer work well...

 

[Claas]

With the writing on a lm317 facing you, the left pin is the adjust., the center pin and the tab are voltage out, and the right pin is voltage in.

 

[duke37]

I believe that the connections as shown in #11 are correct when looking at the labeled side of the LM317T. The output is the centre leg in any case.

Solder can be removed by solder braid, you can even use the braid from the outer of a co-axial cable.

 

[Rleo6965]

#11 was correct and complete with filter capacitor.

 

[c131frdave]

Thanks guys!

 

[c131frdave]

A buck regulator may give more problems if is is noisy.

Can you wrap the output wire around a ferrite ring to help with the noise? Just curious.

 

[Rleo6965]

I just noticed on the LM317T calculator page that the tab where the screw goes through it is labeled as Vout. Is that true? If so, my board is shorted...

Not yet. Your heatshield was not soldered to pcb. Therefore no electrical connection.

 

[Rleo6965]

Can you wrap the output wire around a ferrite ring to help with the noise? Just curious.

Not completely. LM317 was still a good choice.