Getting to grips with AC

Also: P=V^2/R (V squared / R)

So:

Increase V or I increases P

Decreasing R increases P

Don't confuse yourself with the transformer case, a transformer can only increas EITHER V or I , not both.

The file you are downloading, look in the Foundation course first, technical basics. Then look at the technical stuff in the intermediate.

Reply to
Brian Reay
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be used to

chemical energy

pass a loop of conductive material though a magnetic field, natural or manufactured and electrons (amps) will flow in the wire.

thats all a generator is.

Phil Scott

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Reply to
Phil Scott

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You are confused... chemical reactions produce amperage... that is they produce free electrons.. the then flow... the amount of the electrons and the resistance to flow (trying to push them though a small wire for instance) leads to a build up of pressure behind that flow...that pressure is called voltage...

the chemical reaction produces only amperage though...thats it... voltage (the pressure is side effect ...a result of the resistance to those electrons flowing, as more and more are being released)

common box

and different

Bigger batteries, larger reaction basically (you can speed a reaction up and get more amperage but over a shorter time)

you need to draw out these concepts...you will not learn them out of context by trying to absorb random data. (some of wrong or misleading in its presentation)

In DC and AC...larger generator source...more wire turning through a heavier magnetic field. in batteries, more chemical mass reacting.

Phil Scott

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battery ?

leg will

va =va in a transformer... you have asked that question 90 different ways already and seem to be trying to find a way to get output greater than input...its not going to happen...

you can transform high voltage to low voltage but the amperage changes accordingly so that va =va (minus 2% or so losses in the transformer)

Basic law of physics energy cannot be created or destroyed (only changed from potential energy as in a lump of coal...or piece of uranium, to heat or electric energy though a chemical or nuclear reaction)

You owe those trying to assist you some of your own independent study.... you will not understand much until you develop a background from wich to relate to these issues with.

Phil Scott

Reply to
Phil Scott

Phil, I don't know too much about batteries. The chemical reactions that occur tend to leave charge distributed such that there is more negative charge at the anode and more positive charge at the cathode. This charge distribution will have a voltage gradient associated with it. This voltage gradient is detectable at the terminals as a voltage, even if there is no load attached.

Dear OP, a voltage source (a dc voltage) is a fine way to think of a battery. A fancier way to think of them is a voltage source and a small series resistor, but even that is probably beyond present needs. Maybe less is more if it prevents bogging you down with too much detail.

Perhaps the OP would benefit from asking / looking for more links to some structured learning material? I saw one person pass along some links and it seemed like a good idea. Not to say the OP should not use the ng, too. But working out problems and doing calculations would be a very good way to learn, if people know of any resources on the net?

j
Reply to
operator jay

Eh, no. You are confusing EMF and PD.

By your logic if I measure a cell (or battery) with an old fashioned AVO Meter (VOM) then I should get a higher reading than with a modern DMM. That doesn't happen, the VOM will read slightly less due to Kirchoffs Voltage Law.

Reply to
Brian Reay

"Barry Fawthrop" wrote

Lets go way back to the old water analogy.

Volts is water pressure. Like the water pressure in a house: you give the water someplace to go, say opening a faucet, and out it squirts. No pressure, no squirt.

The bigger the opening in the faucet, the less resistance to the flow of water, the faster the water comes out.

The water pressure is like Volts: a measure of how much the electricity wants to flow.

The water flow is like Amps: a measure of how much flows.

The faucet is like ohms (resistance): a measure of how much current will flow for a given voltage.

To get amps to come out of the battery you have to give it a path (pipe) to flow along - say a wire. A wire allows an awful lot of amps to flow, though, and the result is often a fire (for water, a flood). So putting a wire across the battery is a no-no.

A resistor will allow only some current to flow. The equation saying how much current is the famous ohms law: Amps = Volts / Ohms.

If you want to get 1 amp out of a 9v battery then you need a 9 ohm resistor connected from + to -. I would not advise this as 1 amp is beyond most 9 volt batteries and most 9 ohm resistors and they will overheat.

Current in small circuits is measured in 1/1000 of an amp, a milliamp (mA).

A 9,000 (written 9K) ohm resistor will allow a 1 mA current to flow.

-- Nicholas O. Lindan, Cleveland, Ohio Consulting Engineer: Electronics; Informatics; Photonics. Remove spaces etc. to reply: n o lindan at net com dot com psst.. want to buy an f-stop timer? nolindan.com/da/fstop/

Reply to
Nicholas O. Lindan

Ok Jay you now did confuse me (perhaps I was confused at the start)

A chemical reaction (like a battery) produces amperage. then based on the thickness of the wire you get the amount of volts from the same reaction.

Is this right ?

So if I put a thicker wire on a 9V battery I would get more voltage out of the battery, right ?

How does the series of resistor, part play a part in the whole supply of Volts and Amps to a circuit?

Additional links would be great, yes please. Like I said I'm trying to get to grips with how to increase or create power, and thus focusing on how to increase Volts and Amps and P = V * I then yes using Ohms Law you could replace V or I with R V = I * R.

But I would like to stick to V and I. A transformer is a simply way to increase V, so now I'm focused on I.

Thank You to All

Barry

Reply to
Barry Fawthrop

Thanks Nicholas

Ok I follow your water analogy well. size of pipe -> greater flow size of wire -> greater amperage amount of pressure amount of voltage

If I'm right you can control the amount of Amps (I) by using a resistor The larger the resistor small the Amps >R ->

Reply to
Barry Fawthrop

No, in fact the converse.

If you drive a car, with the engine off turn on the headlights. Then try start the engine- as the engine cranks the lights dim. The reason is that the extra current ("amperage") causes a voltage drop across the battery's internal resistance. The exact converse of Jay's novel theory.

I'd ignore Jay's post.

Reply to
Brian Reay

Dear OP,

If you want my advice, the first thing you need to do is forget all about chemical reactions etc. Don't even let it cross your mind. I tell you earnestly and with confidence you won't have any use for such knowledge while learning the basics of electricity, and - very seriously - probably not in the whole remainder of your life either.

Now, if there's something you'd like to know, reply and ask, but don't ask me more than one question at a time. I think it would be a good idea if you gave me a VERY brief description of what you think voltage and current are, or how they work, or what they do, or something about them. Just so I have an idea of where we stand. Don't research it, just tell me what you think.

By the way, I see your response to another poster and it sounds like you're getting things pretty well. About a battery, think of it as a "pre-set" voltage.

Regards,

j
Reply to
operator jay

Dear OP,

If you want my advice, the first thing you need to do is forget all about chemical reactions etc. Don't even let it cross your mind. I tell you earnestly and with confidence you won't have any use for such knowledge while learning the basics of electricity, and - very seriously - probably not in the whole remainder of your life either.

Now, if there's something you'd like to know, reply and ask, but don't ask me more than one question at a time. I think it would be a good idea if you gave me a VERY brief description of what you think voltage and current are, or how they work, or what they do, or something about them. Just so I have an idea of where we stand. Don't research it, just tell me what you think.

By the way, I see your response to another poster and it sounds like you're getting things pretty well. About a battery, think of it as a "pre-set" voltage.

Regards,

j
Reply to
operator jay

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good way to

correct.

Phil Scott

Reply to
Phil Scott

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amperage...

the

(trying to

build

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though...thats

of the

are

based

from the

Jay dint say that, I did...and as jay said later, you get a voltage differential in a battery with no wire connected...thats the build of pressure from the number of electrons set free to move in the electro chemical reaction...attach a wire from = to + an you get a dead short and no voltage after a few tents of a second...connect a very fine wire and you get limited flow and a reduction in voltage potential across the battery terminals.

you will NEVER understand this though unless you work it out for yourself as jay suggests... you have to be pro active... do 'what if' analysis and understand that net energy is never lost or gained, only converted from one form to another... thats physics...you need a clue in that area or you will not understand these electricity issues real well.

voltage

No .. the oposite you would bleed off all the electrons instantly and the pressure behind them (voltage) would drop to zero... but shorting the battery as you have suggested would give very high current flow for an instant or two...thats watts... or voltage multiplied by amperage..

You are not doing your home work or you would know this full well by now.

think of a

source and a small

needs. Maybe

detail.

whole supply

do your homework...this has been explained to you many times already.

more links to some

some links and

the ng, too.

very good way to

or create

You cannot increase or create power by manipulating the aparatus... get a grip man...power in = power out.

voltage alone or amerage alone can be incresed but not in combination unless you spin the gnerator faster or make a larger battery.

You are becoming tedious on these issues.

later.

Phil Scott

and thus focusing on how to increase Volts and Amps

or I

simply way to

Reply to
Phil Scott

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Kirchoffs Voltage

sigh.... try this, let a car battery go dead...no voltage... put it on a charger at 20 amps say for 10 seconds... it will a trace voltage at the point..but not the full rated voltage... put it back on the charger for a minute...the voltage will increase fainlty.

put it on a charger for a few hours and presto...full voltage.

Voltage is a function of the number of electrons freed to move in the electro chemical reaction. a few electrons create a slight voltage differential... a lot of electrons create higher voltage potential...voltage in a battery then is a function of the number of electons free to move though the battery.

QED.

Phil Scott

Reply to
Phil Scott

amperage

a resistor

amount of

control

close but no cigar ...resistance is not a feature of a battery...a battery is a stored source... resistance is applied in a loop connecting each end of a battery...a light bulb is a resistance...it glows when attached to the battery poles.

R has increased

decreased. Right or

I am too out of gas to respond... I give up/

start by getting ohms law right.

Phil Scott

Reply to
Phil Scott

Batteries do have resistance and it is added to the external resistance if you want to calculate the current thru an external resistor. Depending on the battery and the load the internal resistance may or may not be significant. The value of this resistance varies as the battery ages and in various other ways as well (hot or cold etc.).

Reply to
John G

"operator jay" wrote

Or conversely, some find it just dandy to know all about the chemistry and forget all about electricity.

Then there's the psychologists: no chemistry and no electricity either.

Reply to
Nicholas O. Lindan

"Barry Fawthrop" wrote

You can't.

This battery resistance is called 'internal resistance'.

However, different batteries have different internal resistances. All else held constant, a bigger battery will have less internal resistance.

Well designed circuits, and well sized batteries, are not affected by the battery's internal resistance.

Reply to
Nicholas O. Lindan

Not quite true, part of the 'exhaustion process' is the increase of the internal resistance.

Reply to
Brian Reay

What's 'exhaustion process' got to do with the size of the battery?

-- Nicholas O. Lindan, Cleveland, Ohio Consulting Engineer: Electronics; Informatics; Photonics. Remove spaces etc. to reply: n o lindan at net com dot com psst.. want to buy an f-stop timer? nolindan.com/da/fstop/

Reply to
Nicholas O. Lindan

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