Hello , I have built the following regulator in real life, unfortunetly instead of having on cathode 5V I have 2.78.
R7 is the current limiting resistor and th first thing the I found odd is it has 5V voltage drov over it.
Where did I go wrong connecting the TL431?
Thanks

 

hi yef,
This is what I see.
E

 

Why are you using TL431 and not the more popular LM7805?

 

Hello,I have made a video and uploaded it into the drive.
I have checked the connections as shown in the video.
Why its showing 2.78 instead of 5V ? where did I go wrong?
Thanks.

https://www.digikey.be/nl/products/...CBcDaICoBkAsBmAjAQQMoYLQHYARASQGE5cA5QkAXQF8g

https://technionmail-my.sharepoint....ied.view.6f988448-dd5d-4c2c-b7ad-e13de3394db6

 

The junction of R8 and R12 should connect to pin 1. Your PCB traces appear to connect it to pin 2 instead.

Edit: Ignore the above. It applied to the schematic, which has pin numbering different from the physical IC.

 

Hello,So If I understood you corectly I need to remove the old current limiter connection and reconnect it to cathode PIN1 in TL431.Correct?
Thanks.

 

So If I understood you correctly I need to remove the old current limiter connection and reconnect it to cathode PIN1 in TL431.Correct?

Yes. Also note my edit in post #5.