Hello all,
I'm a little curious, I bought a buck converter after I made a similar one myself (one way to learn things ;-)) . Both are according to the data sheet of LM2596. Could anyone tell me what those very small components are between the blue potentiometer and the regulator? There is also one next to the 50V cap. I was guessing resistors but those two beige ones are hard to measure
Thx
The black one could be a 330R resistor.
The brown one could be a capacitor.
Are you able to work out where in the circuit they connect, by following the PCB tracks?
I don't really see any pcb lines (or already an not good enough with electronics anyway). But i found myself a website with some pics of smd components :Identification pictures for Surface Mount Devices (SMD)
It seems that you are right as one is a resistance and the other two are caps. Now i need to figure out why the caps are there 
The datasheet goes into some details about the values needed and what the different components do:
Please crop/resize your picture next time, or Modify and delete the current one and Attach a cropped picture.
In the datasheet linked by CrossRoads you can find the image attached. Looking carefully to your picture you can make the associations that I point in the your picture. So, we only miss one that is CFF.
CrossRoads:
The datasheet goes into some details about the values needed and what the different components do:
http://www.ti.com/lit/ds/symlink/lm2596.pdfPlease crop/resize your picture next time, or Modify and delete the current one and Attach a cropped picture.
I had cropped the pic but uploaded the wrong one. It has been modified.
I know all the components needed and those two small capacitors are not specified in the data sheet.
They are in parallel to the two big caps though so i guess they are to filter out some noise.
Anyway, thanks for the help!
read the data sheet about ripple filter.
it discusses the ripple and a post ripple filter.
the SMT tantalum caps you are looking at are mentioned for the post ripple filter.
basically, they remove the high frequency ripple generated by the switcher.
After read the comment of dave-in-nj I look to the picture one more time, and the capacitor that I miss in the picture should me named "2+". Is connected between GND and OUT+. So this design don't have the capacitor CFF.
dave-in-nj:
read the data sheet about ripple filter.it discusses the ripple and a post ripple filter.
the SMT tantalum caps you are looking at are mentioned for the post ripple filter.
basically, they remove the high frequency ripple generated by the switcher.
Thanks!
That tan parts are ceramic capacitors. The one between the inductor and the chip is extra noise filtering across the output. One side is connected to the tab of the LM2596, which is ground, the other is connected to the inductor and following the copper to the left, to the output.
Electrolytic capacitors, the 100uF 50V on the input and the 220uF 35V on the output, are not very good when the frequency gets pretty high. So the ceramic capacitors are added to handle high frequencies, both short pulses and general noise.
Schematics in datasheets are sometimes rather barebones.
