SS PSU without choke

[fdegrove]

ANODE RESISTOR

Hi,

(Elfa) only had 47k at 10W. Is it bad to have 10W instead of 1W?

It will be inductive and as such be non-linear.

47K is such a common value that you may find it around the corner.
Better take a 1W metalfilm.

Cheers,

 

[Mikael Abdellah]

I have put two choked psu's on my webserver so you can have a look at them. Please tell me what you think, and also tell me how to improve it.

http://213.67.45.70/no_ripple.psu

http://213.67.45.70/no_ripple2.psu

I haven't taken my need for 400V into consideration, I just wanted to test how much a choke could filter my psu. And the results are breathtaking if you ask me.

 

[jan.didden]

Re: ANODE RESISTOR

Hi,



It will be inductive and as such be non-linear.

47K is such a common value that you may find it around the corner.
Better take a 1W metalfilm.

Cheers,

Frank,

Not wanting to split hairs, but an inductive resistor is not necessarily non-linear. Its impedance does change with frequency, but ususally this is a linear change. I mean, all resistors have a tempco, which means the resistance changes with temperature, in a linear fashion.

Jan Didden

 

[dhaen]

Split the hairs even further..

Most film resistors are inductive too. That's why one of the few sanctuarys left for the carbon composition resitor is RF circuitry.

 

[fdegrove]

Re:Splitting hair.

Hi,

That's why one of the few sanctuarys left for the carbon composition resitor is RF circuitry.

Now I know where that noise comes from.

Seriously,carbon comp is not inductive?
I didn't know that.

Cheers,

 

[Bas Horneman]

Mikael,

Bottom line...use the 10watt resistor...until you run into some nice riken ohm, kiwame, mills or dale ns, and just solder the little buggers in and tell us if you heard a difference!
Cheers,
Bas

 

[dhaen]

Carbon composition resistors

Frank,

Seriously,carbon comp is not inductive

If you're in a definite and black & white answers mood, of course.
They are as inductive as the wire connecting them (length for length).
This leads to a resonant frequency of about 4GHz - 10GHz.
Now, my hearing doesn't quite reach that far but maybe yours does

Am I worried
Just don't put one in your microwave oven!

Cheers,

 

[dhaen]

10watt WW in anode

In all seriousness, IMO this is not desirable in the long term.
In the short term, it'll probably be fine.
If you hear any radio stations in the background, you'll know it's time to change it.

Cheers,

 

[BeanZ]

I know that this thread has moved passed this now but for the future: A choke is a term designated to an inductor operating with a DC bias current. The "inductors" used as output filters in switching power supplies are actually chokes because they operate with a DC bias and filter ripple current.

BeanZ

 

[dhaen]

BeanZ,

That sounds the most credible explanation so far.
Do you know the origins?

Cheers,