On 07/14/2016 01:12 PM, Cursitor Doom wrote:
On Thu, 14 Jul 2016 11:53:30 -0400, Phil Hobbs wrote:

Too small an output cap, or too low an ESR? Three terminal regulators
can oscillate. Try hanging 100 uF aluminum electro on the output and
see if it starts behaving better.

The datasheet says output caps are "optional" although I do always use
'em. The one I'd fitted was 1nF which seemed a bit small, so I subbed it
for a 100n but it's made no difference. 100uF seems HUGE! I might try it,
though.


100nF is guaranteed to make a 317 oscillate. Microfarads, me lad,
microfarads.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net