Question for Zeity

[suityou01]

As he is a solder smoke sniffing type.

I'm pottering and one job I have is to mend my mini-itx pc, mythbuntu box.

It was supplied with a 10V laptop "brick" type external adaptor. One day the whole rig failed. Dead.

I have since lost the external adaptor (read as SY02 filed it somewhere), but I do recall it was 10V, but can't remember it's current capability.

No problem as when I use a tinopener on the rig I can see the open frame PSU circuit - model number AD12VC-100-LF.

The properties of this little board are

12V +/- 5%
100W
10A Max.

So firstly I have no frakin clue why PissyWorld supplied it with a 10A brick, but at least that explains why the rig eventually stopped working, ie overcurrent in the external adaptor.

Now, IIRC

100W (Power) / V (12) = I (8.33A)

So I would need a 12V DC PSU say 8.5A?

I have found some online and they strangely mention power factor correction. Why is PFC necessary on a single phase device and should I also be taking this into consideration, or is a 12vDC 8.5A "brick" gonna do the trick?

TIA

[doodab]

As he is a solder smoke sniffing type.

I'm pottering and one job I have is to mend my mini-itx pc, mythbuntu box.

It was supplied with a 10V laptop "brick" type external adaptor. One day the whole rig failed. Dead.

I have since lost the external adaptor (read as SY02 filed it somewhere), but I do recall it was 10V, but can't remember it's current capability.

No problem as when I use a tinopener on the rig I can see the open frame PSU circuit - model number AD12VC-100-LF.

The properties of this little board are

12V +/- 5%
100W
10A Max.

So firstly I have no frakin clue why PissyWorld supplied it with a 10A brick, but at least that explains why the rig eventually stopped working, ie overcurrent in the external adaptor.

Now, IIRC

100W (Power) / V (12) = I (8.33A)

So I would need a 12V DC PSU say 8.5A?

I have found some online and they strangely mention power factor correction. Why is PFC necessary on a single phase device and should I also be taking this into consideration, or is a 12vDC 8.5A "brick" gonna do the trick?

TIA

You seem to have gotten confused with volts and amps.

The DC-DC converter doesn't necessarily need to be fed from a 100W or greater supply, 100W / 10A is probably it's maximum rating. The supply does need to meet the needs of whatever is on the other side i.e. the motherboard, CPU etc.

Oddly enough, PFC is necessary to correct the power factor It's required by law in the EU now because it improves the efficiency of the power network.

[suityou01]

You seem to have gotten confused with volts and amps.

The DC-DC converter doesn't necessarily need to be fed from a 100W or greater supply, 100W / 10A is probably it's maximum rating. The supply does need to meet the needs of whatever is on the other side i.e. the motherboard, CPU etc.

Oddly enough, PFC is necessary to correct the power factor It's required by law in the EU now because it improves the efficiency of the power network.

Can't see where if I'm honest?

Also if the unit needs to generate 100W, energy cannot be created or destroyed so the source PSU should be able to deliver this as well?

[suityou01]

Thanks all.

[doodab]

Can't see where if I'm honest?

It was supplied with a 10V laptop "brick" type external adaptor.

I do recall it was 10V, but can't remember it's current capability.

I have no frakin clue why PissyWorld supplied it with a 10A brick, but at least that explains why the rig eventually stopped working, ie overcurrent in the external adaptor

Also if the unit needs to generate 100W, energy cannot be created or destroyed so the source PSU should be able to deliver this as well?

It converts a maximum of 100W from a 12V supply to the various voltages used within a PC (3.3V, 5V, 12V, -12V). What that means is that if you try and draw more than 100W (or presumably > 10A on any rail given the quoted spec) it probably isn't going to work i.e. voltages will drop below spec or it will shut off.

The power it actually needs to supply depends on what you have connected. If you are only drawing 60W you'll only need to put 65-70W or so in. It's a bit more to account for inefficiency. If you are drawing 100W then the chances are you'll need to put more than 100W in for the same reason. If you are drawing more than 100W then you need a higher capacity DC-DC converter.

[suityou01]

It converts a maximum of 100W from a 12V supply to the various voltages used within a PC (3.3V, 5V, 12V, -12V). What that means is that if you try and draw more than 100W (or presumably > 10A on any rail given the quoted spec) it probably isn't going to work i.e. voltages will drop below spec or it will shut off.

The power it actually needs to supply depends on what you have connected. If you are only drawing 60W you'll only need to put 65-70W or so in. It's a bit more to account for inefficiency. If you are drawing 100W then the chances are you'll need to put more than 100W in for the same reason. If you are drawing more than 100W then you need a higher capacity DC-DC converter.

Ah. Quote 4 is a typo. I meant 10V. As I previously stated 10V the first two times interpolation was possible.

Supply side is 12V, so 100W (as you say add some in for heat loss etc) say 125W in total capability.

P/V = I

125/12 = 10A (Nearasdammit)

Which is what the toothy one said. So all in agreement and I didn't get my volts and amps muddled. A simple typo.

If only we could let this lie there.