Understanding Volts and Amps!!

[Brightspark2]

so cost more to run...................

No there both 50W...

You get charged per kWh...

 

[i=p/u]

yeah nothing more than a safety issue in using 12v downlighters..

 

[Brightspark2]

yeah nothing more than a safety issue in using 12v downlighters..

Yes and constantly changing lamp holders and transformers in them lol...

 

[Darkwood]

Low voltage lamp cost more to run but only fractional as the control gear 230/12 will have losses, this was arguably recouped by the extended lamp life of 12v as they are ramped up and down slower thus less thermal shock to the filament but all changed now that gu10 has interchangable energy saving options with controlled ramp up and down.

If a 50watts lamp is the constant here then ohms law dictates

50w / 230v =0.22amps
50w/ 12v =4.17amps

As already mentioned both lamps use 50watts so this will cost the same at both voltages with a little discrepency afforded by the transformer losses, do remember the filament resistance is changed by design to suit the voltage to give the same light output.

 

[i=p/u]

yeah clear as day now lads, men

 

[Darkwood]

It was much easier to learn in my day with good old 240v as it was devisable by 12v leaving 20 or vice versa...

50/240 = 0.21
50/12 = 4.17

so to confirm change the 12v back to 240 (240v/12v = 20)
then convert the current used at 12v to 240 (4.17amps/20 = 0.21amps)

No current demand difference when transformed to mains voltage.

 

[i=p/u]

i can do the maths its the theory of nothing changes just the filament i didnt know. cheeers big lad or ty man.

 

[Darkwood]

If i recall alot had issues getting their head around this at college me too but it was 25yrs ago ..the way he showed us was to work out the filament resistance of a 50w lamp at 12v lamp then keep the filament resistance the same and calculate what the current would be at 240v....Bang .....although the the voltages and wattages are different as we didnt have 50w diachroic lamps in our day it still made it stick in your mind.

Beer time now so i wont bother doing the sums as im sure you are quite capable :smug: