Quick question

Adam_151 · 16 Apr 2015

As far as I understand it, due to the effect of temperature on the resistance, for a tungsten lamp. The current increases roughly in proportion to the square route of the increase in voltage.... i.e double voltage for a 41% increase in current, which equates to a doubling of the power. The brilliance though, increases in proportion to the cube of the voltage increase so its 8x as bright.

Somewhere the trade-off between acceptable efficiency and lamp life occurs, it is possible to make a lamp which never blows, but would not be worthwhile running! (hence the odd lamp from 80-100 years ago still working!) It is ironic that as GLS lamps are phased out, rough service lamps are not as they are special purpose, however they are ending up in general service as GLS are not available. They are less efficient than GLS and GLS was phased out for green reasons.

JohnW2 · 16 Apr 2015

Adam_151 said:
As far as I understand it, due to the effect of temperature on the resistance, for a tungsten lamp. The current increases roughly in proportion to the square route of the increase in voltage....

I'd have to look it up, but I have a vague recollection that that is roughly correct, at least over some range of voltages.

Adam_151 said:
i.e double voltage for a 41% increase in current, which equates to a doubling of the power.

2 x 1.41 = 2.82 - so nearly three times the power. To get only a doubling of power with a doubling of voltage would obviously require the current to have remained unchanged!

Kind Regards, John

RF Lighting · 17 Apr 2015

As some of you have realised, this was a some what loaded question in response to a statement on the locked power monitors thread.

ban-all-sheds said:
RF Lighting said:

He knows the lights use less voltage. I don't think it's unreasonable for someone to assume less voltage = less power.

Click to expand...

It is completely, utterly, verging-on-the-need-for-permanent-care unreasonable when a lamp is described as 50W.

So, regardless of wattage sometimes less voltage = less power and sometimes it doesn't. But someone with no knowledge of physical science or ohms law should just know when it applies and when it doesn't.

ban-all-sheds · 17 Apr 2015

RF - you are being ridiculous. The scenario you describe is not analogous to comparing a 230V 50W lamp running at 230V with a 12V 50W lamp running at 12V.

On everybody's bill a kWh is a kWh is a kWh.

JohnW2 · 17 Apr 2015

ban-all-sheds said:
RF - you are being ridiculous. ... On everybody's bill a kWh is a kWh is a kWh.

Indeed - but what you are missing (from your position of knowledge) is that there is a fair body of people out there to whom "kWh" is totally meaningless - as far as they are concerned, they might just as well be charged for units of BAS/m² !!

Kind Regards, John

ban-all-sheds · 17 Apr 2015

Doesn't matter.

You don't have to know what a watt is. You just have to know that it's the basis of what you are charged for using for an amount of time.

JohnW2 · 17 Apr 2015

ban-all-sheds said:
You don't have to know what a watt is. You just have to know that it's the basis of what you are charged for using for an amount of time.

The people I'm talking about don't even understand that. The only bit of the bill they understand is in units of £.

Kind Regards, John

ban-all-sheds · 17 Apr 2015

We are going round in circles.

It is not unreasonable to expect someone to be able to read their bill and to know that they are being billed for x thousand somethings.

What you and RF are doing is trying to make excuses for, and portray as perfectly reasonable, people who wilfully refuse to THINK.

JohnW2 · 17 Apr 2015

ban-all-sheds said:
It is not unreasonable to expect someone to be able to read their bill and to know that they are being billed for x thousand somethings. What you and RF are doing is trying to make excuses for, and portray as perfectly reasonable, people who wilfully refuse to THINK.

I don't think you live in the same world as some people. You obviously didn't meet my mother or grandmother, or several other of my past family members!

Kind Regards, John

RF Lighting · 17 Apr 2015

I'm charged for my gas in M³. I have not got a clue how big or small a M³ is, or how my gas usage is divided between my boiler, cooker and fire. I also do not know how efficient each appliance is. All I understand is how many £££'s I have to pay at the end of the month.

I imagine that someone working in the gas industry will have a much greater understanding of these units, and the efficiencies of each appliance.

ricicle · 17 Apr 2015

ban-all-sheds said:
What you and RF are doing is trying to make excuses for, and portray as perfectly reasonable, people who wilfully refuse to THINK.

You must have a very narrow-minded view of life

ban-all-sheds · 17 Apr 2015

RF Lighting said:
I'm charged for my gas in M³. I have not got a clue how big or small a M³ is, or how my gas usage is divided between my boiler, cooker and fire. I also do not know how efficient each appliance is. All I understand is how many £££'s I have to pay at the end of the month.

Indeed.

Would you expect there to be some magic way that 1m³ of gas used by your boiler to be differentiated at the meter from 1m³ used by your cooker, and charged at a different rate?

Would you expect 1m³ of gas used by your boiler to be a different amount of gas than 1m³ used by your cooker?

RF Lighting · 17 Apr 2015

My boiler has the same size gas pipe going to it's the gas fire does, but the boiler gives out more heat. Maybe my boiler runs at a higher pressure than my fire to be more efficient? I have no idea.

ban-all-sheds · 17 Apr 2015

Maybe things do run at different pressures.

Maybe some things are more efficient than others.

So maybe you don't get as good value out of 1m³ of gas consumed by Appliance A as you do from Appliance B?

Would you expect the meter to adjust how many m³ of gas it was registering, depending on the working pressure or efficiency of the appliances?

Would you expect there to be some magic way that 1m³ of gas used by Appliance A to be differentiated at the meter from 1m³ used by Appliance B, and charged at a different rate?

Would you expect 1m³ of gas used by Appliance A to be a different amount of gas than 1m³ used by Appliance B?

RF Lighting · 17 Apr 2015

I have no idea. I've never even thought about it, but I guess if something is more efficient due to a change in pressure or what ever then yes I'd expect to see the meter register less gas. All I know is my boiler uses 'some' gas and it costs me some £'s.

I know it's a waste to leave the gas fire on when I'm out at work, so I don't do it, but I honestly have no idea if it uses more or less gas than my cooker for example.

Just like some people know their lights use 'some' electricity, but have now idea how the amount of light they get is converted into £'s owed.

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