Amperes

[nOOb]

First post here, I'm kind of new to electronics.

I would like to know what the amperes mean on a power supply? Let's say 12V 1Amp

Does it mean the power supply "spits" out 1Amp???
or the power supply requires 1Amp to work?

 

[Sceadwian]

Try Google or Wikipedia before asking questions
Ampere - Wikipedia, the free encyclopedia

Power generally supply voltage, but are only rated for so much current, if you try to draw more current than they can supply the voltage will drop, this can be bad for both the power supply and the load. The resistance of the load and the applied voltage will determine the actual current the load needs, in the real world with motors and active circuitry this resistance becomes a complex impedance which changes for various reasons and under various conditions.

 

[crutschow]

That amperage is the maximum output current, not the operating current. The power supply can deliver anything from 0 Amp up to the maximum (in this case 1 Amp) as determined by the load resistance at 12V.

 

[nOOb]

So basically I could use a 12V @ 15A supply and there wouldn't be any problems? but 12V @ 500mA could cause some problems? Let's say if the device needs 1A

 

[audioguru]

Don't overload a power supply that is rated for only 0.5A but the overload is 1A. It might properly limit the current, catch on fire or blow an internal fuse.

 

[nOOb]

So which one would be better?

12V @ 15A
12V @ 500mA

 

[Sceadwian]

15A, because the 500ma supply doesn't meet the requirements needed by a 1A load, you have a lot of extra current available there, just something to keep in mind, if the circuit that usually requires 500ma's maximum fails spectacularly it has 15 amps of current (or should I say fire) available to it.

 

[nOOb]

I see I've always taught it was the opposite, just like voltage

12V supply in a circuit that requires 6V would dammage the electronics.

 

[Sceadwian]

The supply doesn't really 'supply' amperage though, it has amperage available to be drawn from the load, that's the distinction.

 

[nOOb]

So where are the amps come from?

So the amps are actually doing the work. If that's the case amps=the amount of electrons?

 

[Sceadwian]

The power supply. You need some real basic understanding of voltage resistance and current.
Ohm's law - Wikipedia, the free encyclopedia
Could perhaps help.

 

[nOOb]

So if I understand the amps would actually light a lightbulb? and not voltage.

 

[Sceadwian]

Excluding super conductors amps can't flow without a voltage, but yes the amps the actual current flowing is what's doing the work, can't be done without the voltage.

 

[audioguru]

A light bulb draws its rated current only when it is fed its rated voltage.

 

[nOOb]

So if amps are claculated in coulombs and electrons can be measured in coulombs wouldn't 15A on a circuit that requires 1A fry it? Too many electrons passing through????

 

[audioguru]

Why do nOObs know nothing about electricity or electronics and ask stupid questions?

 

[nOOb]

Because I want to learn. What's so stupid about what I said?

I'm sure you had to learn at some point in your life

 

[crutschow]

Lets try a water analogy. Water pressure is volts. Water flow is amps. The faucet is the load resistance. Thus no matter how many gallons are available, the only amount of water that will flow is determined by the water pressure (volts) and the amount the faucet is open (resistance).

Thus it doesn't make any difference how much current the supply can output, the actual current is determined by the voltage and the load resistance. (And the power output is volts times amps).

Does that make sense?

 

[nOOb]

hhhhmmmmm yes it does now. Thanks

Lets try a water analogy. Water pressure is volts. Water flow is amps. The faucet is the load resistance. Thus no matter how many gallons are available, the only amount of water that will flow is determined by the water pressure (volts) and the amount the faucet is open (resistance).

Thus it doesn't make any difference how much current the supply can output, the actual current is determined by the voltage and the load resistance. (And the power output is volts times amps).

Does that make sense?

 

[audioguru]

What's so stupid about what I said?

I'm sure you had to learn at some point in your life

We talk intellegently about fairly complicated electronic circuits here. There are a few teachers here who might want to teach nOObs the basics but not me.
When I was a nOOb I was taught electronics by teachers who "no speeky zee English". Then I learned the basics by myself.