I've dabbled in low voltage DC electronics for a while, but I'm looking at learning and building a lot more. I intend to build Bob Heil's Pine Board AM Transmitter and part of it is building a power supply for it.
That got me thinking about PC and server PSU's in how they can accept both 240v and 120v inputs. How exactly do they handle the different voltages? Does it just detect if it's 240v and use a center tap or the entire winding if it detects 120v? Sorry if this sounds like a stupid question.
That got me thinking about PC and server PSU's in how they can accept both 240v and 120v inputs. How exactly do they handle the different voltages? Does it just detect if it's 240v and use a center tap or the entire winding if it detects 120v? Sorry if this sounds like a stupid question.
That got me thinking about PC and server PSU's in how they can accept both 240v and 120v inputs. How exactly do they handle the different voltages? Does it just detect if it's 240v and use a center tap or the entire winding if it detects 120v? Sorry if this sounds like a stupid question.
Most PC and server PSUs have a voltage selector switch to be set by the operator.
Small PSUs like for laptops have a wide input range, say 100 to 240 volts because they are designed to accept that range. They do not switch between voltages.
I suppose you could design a PSU that detected input voltage and switched but I do not think they are common at all.
Are you joking?
The majority of power supplies in PCs for the past two decades have been wide input range or autoswitching, they are by far the most common type, there are even dedicated ICs for detecting line voltage and autoswitching.
You made me look. I have three desktops right here and I was sure I was going to find a switch that switches to voltage doubler configuration. You know what I found instead? Stickers that say "230 volts only". On all three.
I remember the 110/220 sliding switches on the older PSUs but I guess they got cheap and removed them.
I went to pccomponentes.com, an online PC components vendor, and most of the PSUs are 230 volt only. Only one says "full range".
Dont look to the crap from Nox..
Look at decent PSU's, like Seasonic, and they all state this:
AC Input Voltage: 100 V - 240 V
And, they have active PFC, who knew..
https://www.pccomponentes.com/seasonic-s12ii-520w-80-plus-bronze
QuoteI suppose you could design a PSU that detected input voltage and switched but I do not think they are common at all.
Are you joking?
The majority of power supplies in PCs for the past two decades have been wide input range or autoswitching, they are by far the most common type, there are even dedicated ICs for detecting line voltage and autoswitching.
Dont look to the crap from Nox..
Look at decent PSU's, like Seasonic, and they all state this:
AC Input Voltage: 100 V - 240 V
And, they have active PFC, who knew..
https://www.pccomponentes.com/seasonic-s12ii-520w-80-plus-bronze
I've a feeling the only way to get a efficiency rating is with active PFC?
The EU mandates limits on harmonics and does not care about how you achieve that.
https://en.wikipedia.org/wiki/IEC_61000-3-2
A passive low pass filter can meet the requirements and is cheaper than active PFC.
I very much doubt that it is cheaper, third harmonic is only 150Hz, so that is a LARGE inductor to keep that out, while an active PFC is like one mosfet, a gapped inductor and a small controller chip, a boost stage running at maybe 50KHz is going to be cheaper then a LC filter cutting off below 150Hz, probably just on the shipping cost never mind anything else!
I think there was an exception in EU rules for psus with less than 75w output, so your monitors may lack active pfc.
TV may use less than 75w, depends on backlight.
if your laptop's brick is over 65w, it should have active pfc.