Voltage drop in LM337 based PS!

[Roushon]

Problem solved!

Thanks to all again for the informative discussions. The problem indeed is solved
by simply adding an 1K resistor from output to ground. I did it for both LM317
and LM337. It surprises me, how more load increased the output voltage.

Regards
Roushon.

 

[nigelwright7557]

I have never been a big fan of the LM317. I prefer the lm78xx regulators.

The LM317 comes into its own with high voltage regulation.

 

[martin clark]

Roushon, thanks for posting the follow-up; it may help others in future.

 

[DUG]

...

The LM317 comes into its own with high voltage regulation.

Or less than 5

🙂

 

[GHJI]

I've got LM337 problems too

I've built a multiple power supply for a TDA1541a based CD player which includes 4 positive lm317 tracking preregulator circuits and 2 negative lm337 ones. All the positives are fine but both negative circuits have a voltage drop when applying a load.
Just as I was etching the circuit I realised the lm337 pinouts were wrong so corrected it by attaching the lm337s to small upright boards intending on correcting the main board if I ever get this one to work and decide to etch another.

 

[GHJI]

Problem solved, I had less than 2 volts with a 50ma load initially, I remade the board and then got 3.55 volts, I increased the 0.1uh output capacitor to 1 uh with a tantalum and got 4.05 volts, I then did the same with the input capacitor and got 4.15 volts then doubling the output capacitor gave me 4.96 volts the same as without a load.