pc power suply

[Zibi]

Hi, should a PC power suply generate AC ???
Mine does, is it ok?

Zibi

 

[David Harmon]

On Thu, 7 Oct 2004 00:08:20 +0200 in sci.electronics.basics, "Zibi"
<P.Zaremba@elka.pw.edu.pl> wrote,

Hi, should a PC power suply generate AC ???
Mine does, is it ok?

No, it should not. There are no AC outputs on a typical PC supply.
Make sure you are operating it with a reasonable load on +5V or all bets
are off. How are you measuring the output?

 

[Zibi]

Hi, should a PC power suply generate AC ???
Mine does, is it ok?
No, it should not. There are no AC outputs on a typical PC supply.
Make sure you are operating it with a reasonable load on +5V or all bets
are off. How are you measuring the output?
Ok, here's the thing...

For lack of a better source I am using a PC supply to power my project.
It's supposed to measure the characteristics of a PV cell. I am using an
ATmega8535.
I have a current source wchich is being used to change the load on a PC
cell.

When I was using a normal (5V/max.500mA) source the characteristics were ok.
Since I need a power source able to provide me with 16A (for the lights) I
used a PC supply.

Now the characteristics have a harmonic distortion (hope it's called like
tat
furthermore, when I am trying to change the intensity of the light by using
a MOSFET driven by the ATmega the processor gets crazy.
I noticed a voltage drop on the base when i connect the lights so i gather
that some current must flow through it.
ergo...(i hope) there must be an AC somewhere.

that's about it

Zibi

 

Zibi <P.Zaremba@elka.pw.edu.pl> wrote:

Hi, should a PC power suply generate AC ???
Mine does, is it ok?
No, it should not. There are no AC outputs on a typical PC supply.
Make sure you are operating it with a reasonable load on +5V or all bets
are off. How are you measuring the output?
Ok, here's the thing...

For lack of a better source I am using a PC supply to power my project.
It's supposed to measure the characteristics of a PV cell. I am using an
ATmega8535.
I have a current source wchich is being used to change the load on a PC
cell.

When I was using a normal (5V/max.500mA) source the characteristics were ok.
Since I need a power source able to provide me with 16A (for the lights) I
used a PC supply.

16A sounds like a lot, if you go over the rating. It might be that the
capacitors won't be able to hold the ripple away.

Now the characteristics have a harmonic distortion (hope it's called like
tat
furthermore, when I am trying to change the intensity of the light by using
a MOSFET driven by the ATmega the processor gets crazy.

Maybe you need galvanic isolation. And it might also be that ATmega won't get
enough "juice". Remember computer stuff won't accept any glitch in power
supply. While motors, lamps etc.. don't care too much

I noticed a voltage drop on the base when i connect the lights so i gather
that some current must flow through it.
ergo...(i hope) there must be an AC somewhere.