Volt Amps and Amps

[dirky]

Can someone tell me as I'm a bit daft,

How many Volt Amps are there in an Amp?

 

[Terranosaurus]

Volt amps are in most instances the same as Watts.

Generators are usually rated in KVA for instance

P=IV

Power = current x voltage but this doesn't apply in things like motors and speakers where there is an inductive load, only in lights etc where it is a resistive load.

 

[dirky]

What I'm looking for is a power supply for my TV which reduces from 240v to 12v but has an output of 4 amps

The only power supplys I can find so far have the figures of 12v - 1.5va or so

I've been quoted £75 for a new power supply from Staples but am sure I can get it cheaper if I know what to look for and how to work out the volt amps to amps

 

[(RIP) PLANK]

what hummingbird is hinting at is 'ohms law' basically volts times amps equals watts or volt amps. Inversley dividing the watts by the volts gives you them amps and visa versa example 10 amps 12 volts + 120 watts.

it is good to do this to get an ideea if you are overloading or not when fitting different combinations of lights etc.

also on the caravan site you can use the amps market on the hook up multiplied by 240 volts and then add up how many heaters kettles etc. you can use at the same time before having to go out in the dark and rain and re-set the trip in the hook up :lol:

as a rule of thumb 3000 watts (3KVA) is usually the max!

 

[Terranosaurus]

what hummingbird is hinting at is 'ohms law'

No I'm not.

Ohms law is V=Ir


P=IV is Joule's first law and actually doesn't apply to most of the things you mention as they are not resistive loads. Its a close approximation but isn't correct.

 

[dirky]

Sorry to break in on my post but what I'm asking is what is a Volt Amp compared to an Amp?

simple answers please :? :? -wor-

 

[Toolbox]

Volt-amps are equivalent to watts (when it applies to devices that absorb all the energy, such as electric heating coils or incandescent light bulbs)

One watt is one ampere of current flowing at one volt.

Watts are typically rated as AMPS x VOLTS or VOLT-AMP (V-A).

 

[Terranosaurus]

It's been answered - twice.

A volt amp is nothing compared to an amp they are two completely different measures, a volt amp is power it's the equivalent of a watt and an amp is a measure of current.

Have a look HERE it should suit your needs. £16.24 + vat & carriage

 

[(RIP) PLANK]

well, I have been told cars dont have valves controling the heating systems any more when thousands do though they are electroing now not levers and wires. Though i must admit they I am not a mechanic by trade! so best let it pass, even though i have held one of these in my hand from a newish ford in recent weeks!

But what i am or used to be is an industrial electonic engineer, started with full city and guilds as an aprentice and then HND, BA, MA, and presentyl M.Phill. I have to agree that toolbox is right he gives pretty much the same explanation as me! And believe it or not I also did all three parts C&G as a TV engineer in the mid 1980's amongst various other thread including hydraulic and pneumatic fitting, psychology and social sciences, leading to now researching in doctor patient relationships!

going through my head still are all sorts of bizzare laws and formulas from boyles law to the formulas for inductive reactance and resonant frequency. Though in practical terms they are rarely used in our modern world of throw away devices. But I will stand corrected for the sake of not taking the bait on yet another argument, it reminds me of why I started abstaining from posting in the first place!

 

[(RIP) PLANK]

It's been answered - twice.
A volt amp is nothing compared to an amp they are two completely different measures,

sorry i missed the bit where anyone suggested it was? anyone care to fill me in?

 

[rossco]

Ok it all goobly gook to me but and to stop a re volt this site might help with watts watt in watts and I amp kidding :lol: :lol:


http://www.everything2.com/index.pl?node=Volt amp

 

[terranokid]

I thought Boils law stated that once the kettle 2000w has boiled The wife can bring me a cuppa 87.45 degrees celcius with a sugar to coffee ratio of 2-1 and a dash of milk.

 

[(RIP) PLANK]

beleive it or not boyles law relatresw to the properties of compressed gasses, anyway, sorry if i went on a bit but some people do come over a bit 'know-it-all' on the odd occasion! advice is great but not when it onvolves trying to look good at other members exspense!

 

[Thomas-the-Terrano2]

for a transformer, try towsure. they do a unit which plugs into mains and drops to 12v with a cigar lighter socket. failing that try maplins, reckon the sort of transfomer used to use with cb in house would do job.

the towsure job is designed to run these portable cooler boxs so should have no problem with a telly.

 

[dirky]

Thank you all very much for the input,, I've printed out the relevant info so that I can keep it cos I'm a thicko in the electrical depot,

us welsh are mostly known for creaming the lamb you know :!:

That's why you see sheep running away from the farmer when he's got his wellies on.

 

[Terranosaurus]

Plank - I answered it, then you answered it, thats where it was answered twice, as for trying to appear good at other peoples expense, you started "correcting" things with incorrect statements about Ohms law.

 

[jims-terrano]

Possibly the best idea is to simply take your power supply into Maplins and ask for one of them. If your unsure or confused try that.

Jim T

 

[supertaff]

Hey Dirky, take a trip down to LLansamlet, go in to MAPLINS, and let them sort it out for you ............ PROBLEM SORTED !!!!!!!
Don't forget to load half a ton of steam coal to fire up the boilers on your cat's whisker telly !!! :lol: :roll:

 

[dirky]

am going down to Llansamlet today with power supply in hand, hope it's not going to cost more than the telly - you know what these things are like :!:

 

[supertaff]

They are pretty good at Llansamlet ... I get a lot of stuff from there.
Have you noticed all these bacon .... oooppppssss sorry .... HAM radio operators showing their call signs on here ? So not to be outdone .... this is SIERRA BRAVO 75 ( honorary member of the Star of Asia [ Jakarta] and 1 Alpha Tango DXing clubs ) signing off !!! :twisted: :twisted: :twisted: