Electrical calculations (1 Viewer)

Jan 16, 2014
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Where V = Volts - Voltage
I = Amps - Currant
R = Ohms - Resistance

The illustration shows a simple way to remember the three formulae.

upload_2014-12-20_16-11-12.png


From the middle pyramid, we can deduce that I = V/R (i.e. that current flow increases with

increased voltage but reduces with increased resistance).

Where E = Volts - Voltage
I = Amps - Currant
R = Ohms - Resistance
W = Watts - Wattage

You can calculate the amount of power if you know two of the three electrical values – voltage, current and resistance.

See the formulae in the wheel (E, like V, is used to indicate voltage).


upload_2014-12-20_16-14-32.png


e.g. I = W/E or E/R
 
Aug 19, 2014
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The only formula I can ever remember is:

IVy watts is a powerful girl.....
 

Gellyneck

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Jun 5, 2014
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More than toes wet now!
SMA is no a bad formula!:xblush:

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Peter A Forbes

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Nov 23, 2014
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I have always used E rather than V for volts, all the formulae I remember and use have that notation.

In most daily usage you only need the basics to work out loadings, and in AC calculations Watts = VA X pf or (Volts X Amps) X power factor.

You shouldn't technically use Watts for AC loads unless their power factor is Unity or 1, ie: purely resistive loads.

Peter
 

scotjimland

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Jul 25, 2007
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I have always used E rather than V for volts, all the formulae I remember and use have that notation.

In most daily usage you only need the basics to work out loadings, and in AC calculations Watts = VA X pf or (Volts X Amps) X power factor.


except on this thread.. :xrofl::xrofl:;)

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Minxy

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Aug 22, 2007
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If you think of it as one of the following you won't go far wrong as a basis to then do other calculations:
  • the first two items, amps and volts, appear earlier in the alphabet than watts, so remember to multiply the first two to get the last ...

  • another way, always remembering it's a multiplication you're doing ... just scratch your head and think ... 'Watts the answer', ie A x V = W
:xThumb:
 
Jul 29, 2007
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My old maths teacher at college, said don't remember formulas, remember answers, like 100c is 212f, play around with 9/5 or 5/9 +or- 32 till it works out right. 250volts at 4amps is 1000watts.

Ian
 
Jan 29, 2014
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So if I put my 2000w electric fire on for 24 hours at 8.7 pence per kwh
how much would it cost me?
 

Minxy

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Aug 22, 2007
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Minxy

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Aug 22, 2007
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a better duvet is a lot cheaper
A hoodie and bedsocks works well as does a nice hot dog on your feet! :D

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Minxy

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Aug 22, 2007
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A hoodie and bedsocks works well as does a nice hot dog on your feet! :D
nah can't stand stale bread and fried onions on my feet
Neither can I ... so I have one of these ... although when she lets out one of her farts it smells like hot dogs! :D

Tazzy on sofa.jpg
 
Nov 6, 2013
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I'll stick with power calc and cable sizing Apps ta ;)

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Jaws

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I have always used ( and taught ) is AVO
Avo is a well known make of meter and is always easy to remember
Same as above really but if you draw it like this:
avo.jpg



It makes things real easy to remember
Amps Volts Ohms

Note where the cross is...
So you want to know what the voltage is ? A X O ( amps times ohms )
Want to know what amps are gonna be drawn ? V
/ O ( volts divide by ohms )
Or what he resistance is of a circuit ? V
/ A ( volts divide by amps )

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Minxy

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Aug 22, 2007
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