Lm337

M

Melfior_Ra

New Member

• Feb 27, 2013

• #1

Hi everyone.

I am trying to build a double power supply, a simple one with lm 317 and lm337 - nothing special.
The positive rail works ok, also the negative rail but on negative the minimum voltage is -0.7V instead of -1.25. I used lm 337t p+ , two of them with the same result.
What is happening?

Thank you in advance

 

K

kubeek

Well-Known Member

Most Helpful Member

• Feb 27, 2013

• #2

most likely you have it connected wrong. 317 has the pins adj, out, in for a to220, and the 337 has them adj, in, out. Next time check the datasheet first

 

audioguru

Well-Known Member

Most Helpful Member

• Feb 27, 2013

• #3

This is what is shown in the datasheets:

 

Attachments

• LM337, LM317 pins.png

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M

Melfior_Ra

New Member

• Feb 27, 2013

• #4

The regulator is connected corectly. I checked it before i post

 

K

kubeek

Well-Known Member

Most Helpful Member

• Feb 27, 2013

• #5

Can you post a schematic of how exactly you have it connected?

 

M

Melfior_Ra

New Member

• Feb 27, 2013

• #6

The pcb is made with proteus, I only routed the nets.

 

Attachments

• post.PDF

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