Hi guys, mind helping :D

[walshy155]

Hi guys, I'm having trouble, understanding the difference between AMPS and VOLTS, I'm not really good at electronics, My stronger points are astronomy and computer science. But I need help understanding, because I have two power supplies taken from old chargers, etc.

 

I dont understand why a 9V 2.2A is more powerful than a 15V 1.2A charger?

 

anyone care to explain?

 

It is much appreciated if you help me.

 

Thanks.

[ewmon]

Who said one was more powerful than the other, and how do you intend to use them?

[swansont]

There are certain analogies with fluid flow.

 

Current, measure in Amps, is the amount of charge flowing per unit time. Which is like the amount of water going through a hose. But you can have an amount of water going through a big hose very slowly, or through a small hose very quickly, and have the same flow rate. The amount of energy per particle (or for a standard amount of particles) it has is the potential, measured in Volts. The product of the two gives you the power.

 

The 9V, 2.2 A charge draws more power because the combination of number of electrons flowing and energy per unit charge is larger, though in this case by a relatively small amount (1.8 Watts)

[walshy155]

So I still dont fully understand, but how is 9V more powerful than 15V?

 

Ohh and I intend to use them to do electrolysis in water, any help on that?

[swansont]

So I still dont fully understand, but how is 9V more powerful than 15V?

 

Ohh and I intend to use them to do electrolysis in water, any help on that?

 

Volts isn't power. Power is the combination of the energy each particle has, and how often they go by. I think part of the problem here is that the results are close, and the answer isn't obvious.

 

Would you rather be punched 10 times (the current) by someone who is strong (potential, or Volts), or 25 times by someone (more current) who is 90% as strong (smaller potential)? Hit once by a 100 mph fastball, or twice by a 95 mph fastball?

 

 

Water has a threshold under which it will never work, but it's around 1.25 V; in practical application you need 2V or so. You should be fine.

[walshy155]

So say I have a power supply of 1V 10Amps

 

and a power supply of 50V 100milliamp it will be less powerful?

 

To be honest, I'm still having a hard time to understand.

 

Hmm so I think what you all mean is the voltage is how much amps can be pushed through, and the amps is actually how much is being pushed through?

[TonyMcC]

This is more tricky than at first appears. The rating on the power supplies will be a given maximum and only developed when connected to the value of resistance load that results in the maximum rated current. Even that ignores internal resistance of the power supply. What I am getting at is if both power supplies are connected to a high resistance load the 15V power supply would produce more power in the load than the 9V power supply (and in both cases less than the maximun rated power). If you are considering electrolysis of water this may well be a high resistance application.

[walshy155]

Thanks for replying but, I have read many webpages now on volts and aps, but I dont get it LOL.

 

All I want to know now is what is voltage and amps?

 

I always thought voltage was a measurement to measure how much power was there, but what the heck is amps?

 

I have seen a few comparing it with water, and how fats the water is flowing and that.

 

 

What is the difference from them both?

[imatfaal]

to be brutal Walshy - if you can't understand these basics please don't go connecting up electrical supplies to water. water and electricity don't really mix. there are lots of basic tutorials on the web. if you have a particular reason to be electrolysing water then maybe some hobby sites will give more usage specific guidance - but its really not something to just try out for a laugh

[walshy155]

Fine, thats all I want to know now is the difference of AMPS and VOLTS, and I have done electrolysis a while back.

[TonyMcC]

Put simply volts push electrons around a circuit rather like a pump pushes water around pipework. Another name for the voltage is electro motive force usually abreviated to e.m.f..

The flow of electrons going around the circuit is called the electric current and is measured in amps. This is similar to thinking about water flowing around pipework which could be measured in gallons per hour.

Voltage is a force. Current is what results from that force.

[walshy155]

So voltage is how much water can be pushed, and amps is how much water is being pushed?

[TonyMcC]

Rather simplified - but yes.

[walshy155]

So If I was shocked by 200v with a current of 10miliamp, it would not hurt?

 

But if I was shocked by 200amps and 1 volt it would sting horribly?

[TonyMcC]

I'm sorry but you are getting a bit out of your depth here. I'll just say that touching 200V would certainly hurt - in fact may well kill you.

Touching 1V would be unnoticed by you. The reference to 200A is immaterial as The "force" of 1V could never force that amount of current through you.

[swansont]

One question that occurs to me is if you are using power (or powerful) in the physics sense (energy/time) or in some other way. It has a specific meaning.

 

If you drop bricks from a window, current is how often you are dropping the bricks. The voltage is analogous to what story (height) you are dropping them from, since energy proportional to h. No matter what story you are on, if you have no bricks (no current), you can deliver no power.

 

As TonyMcC notes, a power supply rating is not necessarily what a circuit is actually experiencing.

[walshy155]

But I also read somewhere else , If I was shocked by a couple hundred volts with low amps it would not hurt, but if it was olads of amps on a low voltage powersupply it would hurt.

 

I thought I knew it by saying "So voltage is how much water can be pushed, and amps is how much water is being pushed", but clearly I dont know, voltage is the measurement for

 

 

Just watched this, now I knwo

 

thanks all anyway!

[swansont]

High voltage/low current is a taser. It is my understanding that they hurt quite a bit.

 

Current is what kills you because your body actually interacts electrically — current disrupts that. Several milliamps going through your heart cause it to stop working properly.

[ewmon]

Voltage is the force pushing the electrons. The current results from that force pushing against a resistance, so a small resistance allows a large current and a large resistance allows only a small current.

 

The ratings listed on your power supply are telling you the voltage that will push the electrons and the maximum current it can continuously push without overheating or burning out.

 

Electrical power is computed as volts times amperes (with units in Watts), so

 

9 volts × 2.2 amps = 19.8 Watts maximum power output

 

15 volts × 1.2 amps = 18.0 Watts maximum power output

 

to be brutal Walshy - if you can't understand these basics please don't go connecting up electrical supplies to water.

I totally agree, and I've worked with electricity for many years.

 

But I also read somewhere else , If I was shocked by a couple hundred volts with low amps it would not hurt, but if it was loads of amps on a low voltage power supply it would hurt.

Whatever you read was written by a bunch of ignoramuses. If your body is hit with a couple hundred volts, and the power supply can support the current that results from it, it'll get really ugly really fast (so prepare for a trip in an ambulance, maybe to the morgue). Almost guaranteed too, that a tiny power supply will burn itself out trying to pump as much current as possible through you, so don't think that the listed ratings will save your life — they won't.

[HerpetologyFangirl]

My mind is boggled from reading too many of these posts... Electronics was always one of my weak points. Would've failed it without all of the helpful equations, and my even more helpful Dad, who is a genius (when it comes to electronics, engineering, marine nautical stuff, and DIY anyway).

[walshy155]

OK So, I kinda get the point, say I have a 12Volt supply @ 1AMP, and a 12Volt supply @ 5@, what would be the difference?, is it that the voltage is being pumped faster?

[TonyMcC]

OK let's try to straighten this out.

If you have a power supply RATED at 12V, 1A the MAXIMUM current it could supply continuously without it being damaged is 1A. It could light a 12V, 12W lamp.

If you have a power supply RATED at 12V, 5A the MAXIMUM current it could supply continuously without it being damaged is 5A. It could light a 12V 60W lamp.

If you have a 12V power supply which is actually DELIVERING 1A then it is forcing 1 coulomb of electricity per second through a load which could be a 12V, 12W lamp.

If you have a 12V power supply which is actually DELIVERING 5A then it is forcing 5 coulombs of electricity per second through a load which could be a 12V, 60W lamp.

A coulomb is a huge number of electrons(Approx 6.25 x 10^18) and 1 coulomb per second is 1A.

[walshy155]

That dont really explain much.

[TonyMcC]

Sorry walshy - it's the best I can do - over and out!

[ewmon]

OK So, I kinda get the point, say I have a 12Volt supply @ 1AMP, and a 12Volt supply @ 5@, what would be the difference?, is it that the voltage is being pumped faster?

Pumped faster? No, electrons flowing through a load, such as a light or toaster (or water), move at the same speed regardless of the voltage or the size of the load (and the resulting current).

 

Amperage = current = amount of electrons. So, it can pump more electrons.

 

Walshy, you might best think of electricity using the water pipe analogy. In this analogy, volts ~ pressure, current ~ flow, resistance ~ restriction.

Edited November 20, 2010 by ewmon