900G power supply? Won't turn on (obvious blown caps)

[pedro]

Re: 900G power supply? Won't turn on (obvious blown caps)

I was never confused. I haven't changed a thing.

You were carrying on about increasing ESR lowering the dissipation in a cap.

I'm not sure why you're confused.
Perhaps it's your English comprehension.

I'm not confused. Increasing ESR in a cap will increase the losses in that cap. Period.

The Ripple that doesn't go through the cap goes through the IC [load].
Less through the cap -> more through the load.
Not sure why you can't comprehend that. It's simple.

It all is. But I'm still unclear why YOU are consused about the increase in ESR resulting in an increase in dissipation in the cap.

Psst - Ripple is AC.
ESR doesn't affect the DC.
DC is irrelevant to a discussion about Ripple.
ESR doesn't 'care' if the DC is 5v or 500v.
.

Of course. Did I ever claim otherwise?

[PCBONEZ]

Re: 900G power supply? Won't turn on (obvious blown caps)

You were carrying on about increasing ESR lowering the dissipation in a cap.

It does.
It moves the dissipation from the cap [where you want it] to the load [where you don't want it].

I'm not confused. Increasing ESR in a cap will increase the losses in that cap. Period.

No..
1 - It reduces it -in the cap- installed.
2 - If you increase ESR it's not -THAT- cap anymore, you changed the cap.

It all is. But I'm still unclear why YOU are consused about the increase in ESR resulting in an increase in dissipation in the cap.

1 - It's not tthat same cap.
2 - As I said, a cap with higher ESR will have less ripple current going through it.

Less current through cap, same volts, less watts. -> less heat.

It's called Ohms Law.
Please review it.

Of course. Did I ever claim otherwise?

Yes, you did.

.

[pedro]

Re: 900G power supply? Won't turn on (obvious blown caps)

It does.
It moves the dissipation from the cap [where you want it] to the load [where you don't want it].

AAARRGGHH!!

And more AARRGGHH!!

No..
1 - It reduces it -in the cap- installed.
2 - If you increase ESR it's not -THAT- cap anymore, you changed the cap.

1 - It's not tthat same cap.

It IS the same cap, but its ESR is increasing - which is exactly what I originally posted back in post#9. Do try to stay on track.

2 - As I said, a cap with higher ESR will have less ripple current going through it.

No it doesn't. <deep breath>

Less current through cap, same volts, less watts. -> less heat.

It ISN'T the same volts. See below or revisit post#16.

It's called Ohms Law. Please review it.

And then in post#20 you stated:

Psst - Ripple is AC.
ESR doesn't affect the DC.
DC is irrelevant to a discussion about Ripple.
ESR doesn't 'care' if the DC is 5v or 500v.

I asked (post#21) "Did I ever claim otherwise?" you responded:

Yes, you did.

Care to point out where?

I'm not sure whether you are being deliberately obtuse, argumentative for the hell of it, or just plain don't follow. I believe everyone is worth some effort to enlighten them, so here goes. I'll give it this one last go to explain why you're mistaken. Please try to keep up - I'll go through it slowly.

The ripple (AC) output of a switcher is a CURRENT SOURCE. The ripple current is directly related to the DC load current. So in a working piece of equipment (e.g. monitor) where the DC load is established, the ripple current is substantially constant.

The low-ESR filter caps are designed to shunt the overwhelming majority of that ripple current. As I explained in post#16, as the ESR rises with deterioration of the cap(s), the current through the cap(s) doesn't reduce by anything like the same proportion, and the I²R losses in the cap(s) rise. Refer again to the sample numbers in that earlier post#16 to understand why.

If you are having trouble understanding this, I suspect you are beyond comprehending something that is fairly basic.

[PCBONEZ]

Re: 900G power supply? Won't turn on (obvious blown caps)

It IS the same cap, but its ESR is increasing - which is exactly what I originally posted back in post#9. Do try to stay on track.

"Do try to stay on track."
ME stay on track?

This thread is about helping geocrasher find replacement caps.

If you want to ramble on expressing you MISGUIDED ideas and theories about how caps work go open your own thread.

.