Power Supply
Turns wall power into the steady DC the chips want.
How big?About the size of a shoebox cut lengthwise.
Real: What it looks like.
Keys: arrows rotate · + / − zoom · 0 reset · 1–4 views · S signal · T tour · L labels · Space spin. Models are stylised and built from code: proportions are honest, details are simplified.
What it is
Electricity arrives as AC, alternating back and forth many times a second. The power supply rectifies it, smooths it with big capacitors, steps it down through a transformer, and outputs steady DC.
Good server supplies waste only a few percent as heat. They come in groups so one can die without the server noticing.
Why AI needs it
An 8-GPU AI server can draw over 10 kilowatts, as much as several homes. Every percent of efficiency saved is real money and less heat to remove.
Every labeled part
- 1
AC inlet
Power from the rack's power strip comes in here.
- 2
Bulk capacitors
Store energy to smooth the ripples out of rectified AC.
- 3
Transformer
Steps the voltage down. It switches at high frequency, which keeps it small.
- 4
Heat sinks
The switching transistors run hot; these fins shed the heat.
- 5
DC output
Typically 12 V or 54 V DC into the server.
- 6
Fan
The supply cools itself.
Try it · concept lab
Fill a rack
Add servers until something gives.
Rack type
dashed line = what the rack can power and cool
Rack draw
43 kW
≈ US homes (avg)
36
Verdict
fits
Assumes ~10 kW per 8-GPU server plus ~2.5 kW for switches and fans; an average US home uses about 1.2 kW around the clock. Rough figures.
Big idea: AI racks are limited by power and cooling, not space. That's why liquid cooling and new power designs matter.
Swap it: other ways to do the same job
Rack power shelf + busbar
One shelf converts power for the whole rack and feeds a DC busbar. Fewer conversions and simpler servers.
Higher-voltage DC
Higher-voltage DC to the rack is under discussion for the biggest AI racks: less current, thinner copper.
Battery backup (UPS)
Not an alternative but a partner: it bridges the seconds before generators start.
Talk about it
- Q1
One AI server can use as much power as several homes. What uses the most power in your home?
- Q2
Some power always turns into heat instead of useful work. Why would wasting a little less power save a lot of money?
For grown-ups: there are no right answers here. Ask a question, then ask "why do you think that?" The reasons matter more than the answer.
Printable question sheet (PDF)