Can someone explain how amps work in a psu?

dirtbikeryzz

New Member
I know that its all about amps not watts but I don't get how it works because I though you only get so many amps from an outlet as it is. Please explain.
 

Yeti

VIP Member
dirtbikeryzz said:
I know that its all about amps not watts but I don't get how it works because I though you only get so many amps from an outlet as it is. Please explain.
It actually is about watts at each given voltage "rail" (12V, 5V, and 3.3V), but it's common to just use the amperage rating for the rail instead. It doesn't matter since power (watts) is amperage times voltage, so saying you need 30 amps on your 12V rail is the same as saying you need 360W on your 12V rail (how they actually come up with the rating, on the other hand, is a different story). What comes out of the wall is at a constant AC voltage (~120V for US) with the current limited by fuses or circuit breakers. The computer power supply takes the 120V AC from the wall and converts it to DC in the voltages mentioned before; power is conserved, amperage is not.
 

Computer_Freak

Active Member
your right about the power. Power = Voltage x Current (VxI)

but as voltage is consistant with all PSU's (12v, 3v, 5v etc) it comes down to amperage.

the more amps it can deliver, the higher the power delivered is.

my PSU has 60 amps on the 12v line (rail, same thing), so that means the 12v rail can deliver 720W of power.

if the amps are lower, it means that the wattage is spread across other rails, or it just cant deliver the current needed...

the 12v rail is the most imporant rail, so you want most the amps there, to get the most out of the PSU

that is usually why the highet teh wattage rating, the more amps on the 12v rail.

But always check to see the power on the 12v line. I have a 750W PSU, with 720W on the 12v rail.

try get a power rating on the 12v rail as close to the power of your PSU.
 
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dirtbikeryzz

New Member
Ic, reason asking is because I had a pc built for me and the guy put a 750 watt psu on it and i thought it was kinda low for the pc but idk.
 

Computer_Freak

Active Member
Ic, reason asking is because I had a pc built for me and the guy put a 750 watt psu on it and i thought it was kinda low for the pc but idk.

ive got a 750W on my system (its a Corsair, so its the best IMO)

more than enough to run my system, with many more extras...
 

Fredrik

New Member
Hi there

I know that its all about amps not watts but I don't get how it works because I though you only get so many amps from an outlet as it is. Please explain.

In actuality, the amplifier generates a completely new output signal based on the input signal. You can understand these signals as two separate circuits. The output circuit is generated by the amplifier's power supply, which draws energy from a battery or power outlet. If the amplifier is powered by household alternating current, where the flow of charge changes directions, the power supply will convert it into direct current, where the charge always flows in the same direction. The power supply also smoothes out the current to generate an absolutely even, uninterrupted signal. The output circuit's load (the work it does) is moving the speaker cone.

Need to know more do ask.... :cool:
 

Jamin43

banned
I know that its all about amps not watts but I don't get how it works because I though you only get so many amps from an outlet as it is. Please explain.

Watts = Volts x amps

Standard US household outlet is 15 Amps @ 120 volts = 1800 Watts

a quality 600W PSU converts the Watts at 120 volts to a usable 12 volt rail that's roughly 12 volts x 50 amps to work with your parts.

The numbers above are not to exact scale - but the concept should help explain the question I think you were asking.
 

Motoxrdude

Active Member
In actuality, the amplifier generates a completely new output signal based on the input signal. You can understand these signals as two separate circuits. The output circuit is generated by the amplifier's power supply, which draws energy from a battery or power outlet. If the amplifier is powered by household alternating current, where the flow of charge changes directions, the power supply will convert it into direct current, where the charge always flows in the same direction. The power supply also smoothes out the current to generate an absolutely even, uninterrupted signal. The output circuit's load (the work it does) is moving the speaker cone.

Need to know more do ask.... :cool:

He's asking about PSU, not audio amplifiers lol
 

dirtbikeryzz

New Member
In actuality, the amplifier generates a completely new output signal based on the input signal. You can understand these signals as two separate circuits. The output circuit is generated by the amplifier's power supply, which draws energy from a battery or power outlet. If the amplifier is powered by household alternating current, where the flow of charge changes directions, the power supply will convert it into direct current, where the charge always flows in the same direction. The power supply also smoothes out the current to generate an absolutely even, uninterrupted signal. The output circuit's load (the work it does) is moving the speaker cone.

Need to know more do ask.... :cool:


Lol I'm not hooking up subs...
 

tlarkin

VIP Member
Amperage = bandwidth or frequency. Imagine you have a garden hose pumping out water. The higher the pressure of water the more water can flow through it. The higher amperage on a 12v rail means the more power can flow through it.
 

schw32m

New Member
Formulas for DC (Direct current) circuits

51d280da96e40cfaec5873d0892994ae.png

877ff7137ef7386990d2ccde60755fac.png

3bfbca8af04359349dcfd73790c0be95.png


where V = voltage difference (SI unit: volt), I = electric current (SI unit: ampere), R = resistance (SI unit: ohm), P = power (SI unit: watt).

So to put it simply, the more current(amps) that can flow through a wire at a given voltage, the higher power(watt) the circuit within the limitations of the supply wire.
 
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FATALiiTYz

New Member
Amperage = bandwidth or frequency. Imagine you have a garden hose pumping out water. The higher the pressure of water the more water can flow through it. The higher amperage on a 12v rail means the more power can flow through it.

Much better;) Just the answer I was looking for aswell, thanks.
 

Fredrik

New Member
lolzzz

He's asking about PSU, not audio amplifiers lol

lolzzz my mistake guys... so here I go with the right one I hope lolzz...
If there is any one component that is absolutely vital to the operation of a computer, it is the power supply. Without it, a computer is just an inert box full of plastic and metal. The power supply converts the alternating current (AC) line from your home to the direct current (DC) needed by the personal computer. In this article, we'll learn how PC power supplies work and what the wattage ratings mean.

In a personal computer (PC), the power supply is the metal box usually found in a corner of the case. The power supply is visible from the back of many systems because it contains the power-cord receptacle and the cooling fan.

Power supplies, often referred to as "switching power supplies", use switcher technology to convert the AC input to lower DC voltages. The typical voltages supplied are:

* 3.3 volts
* 5 volts
* 12 volts

The 3.3- and 5-volts are typically used by digital circuits, while the 12-volt is used to run motors in disk drives and fans. The main specification of a power supply is in watts. A watt is the product of the voltage in volts and the current in amperes or amps. If you have been around PCs for many years, you probably remember that the original PCs had large red toggle switches that had a good bit of heft to them. When you turned the PC on or off, you knew you were doing it. These switches actually controlled the flow of 120 volt power to the power supply.

mmm now what you say...:D
 
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