How many milliamps in 1 amp?

Malestrom

rygon wrote:

yes it is 6.9W ...but how could a 11W bulb take less than 6.9W?????

Because there are two PIR's at 6.9W each...

2ax

gord115 wrote:

So does this mean my secutity light are using 6.9 watt even when they are idle i.e during daylight.
I could have an 11watt low energy light on all night for less than that!

it's costing you about £3 a year - you could switch the pir unit off in the daytime too, but I suspect you'd forget to turn it on again

2ax

rygon wrote:

yes it is 6.9W ...but how could a 11W bulb take less than 6.9W?????

because the light would only be on half the time

Mr_Skint_2

gord115 wrote:

So does this mean my secutity light are using 6.9 watt even when they are idle i.e during daylight.
I could have an 11watt low energy light on all night for less than that!

Answer buy a guard dog and take it for walks to get some exercise
and use the pooh to make a compost heap that heats water that is turned
into electricity to recharge some batteries for your light..... :rolleyes:

2ax

that would definitely cost more than £3 a year :rotfl:

steady__eddie

Whose pooh would I have to use ?
The dogs, mine or both ?

gazza1988

just to clarify,
voltage is electrical pressure. voltage is how fast it moves (i.e 400,000v+ for national grid)
amps is the tingler, thats why voltage stays constant and amp change (have a look at your board, 6amp for lights, 32amps for ring, and 40amps for cooker and/or shower)

a little fact for you it takes 50-80mA to kill a human. but dont worry, if you have a rcd fitted then you are protected so that it trips at 30mA so you feel it but it doesnt kill you. if you dont have a rcd fitted then you fuse board is out of date.

and 215v in your house that is one heck of a volt drop,

the usual is 230-240v if you get that then there is nothing to worry about.

a little lesson in electrical mathematics, there is a formula you can use called the power formula, which is: Power (watts) = U (volts) x I (amps)
(yes the symbol for volts is actually U and amps is I)

so the answer to the original question is P= 230x0.03 = 6.9w (as previously stated,

in regards to the varying voltage question. you get the voltage varying from 230v to 240v, anything outside this bracket then contact your supplier. volts varies from substation to substation. the reason why is even more geeky than the formula above.

moonrakerz

gazza1988 wrote:

jt.

a little lesson in electrical mathematics, there is a formula you can use called the power formula, which is: Power (watts) = U (volts) x I (amps)
(yes the symbol for volts is actually U and amps is I)

The SI symbol (the universally accepted symbol) for voltage is V; U is VERY, VERY rarely used, this post was the first time I've seen it mentioned in about 40 years ! A more commonly used, albeit still rarely, alternative is E. A known voltage is always referred to as V: eg 240V NOT 240U.

Likewise the SI symbol for current is A, although I is sometimes used as an alternative in a general sense as you have used it above, ie: as an indeterminate quantity. A current of 6 amps is always referred to as 6A, NOT 6I.

To be really pedantic, although the domestic mains voltage in the UK is referred to as 230 VAC, it is, in fact, and has been for many, many years 240 VAC. Most of Europe uses 230, because previously they used 115. The EU in its infinite wisdom decided that everyone should use the same voltage, and that would be 230. For the UK to change its supply to 230 would have cost billions, so the change was accomplished by changing the tolerances. So even though the voltage was actually still 240 you could call it 230 - aren't these politicians wonderful !!

Fifer

U is archaic. E is still seen but V is the SI unit. The UK mains voltage used to be 240VAC +/-6% (which is a range of 254.4 - 225.6VAC). It is now respecified as 230VAC +10%/-6% (which is a range of 253 - 216.2VAC) so the poster who was seeing 215VAC is getting a below spec supply, has faulty upstairs wiring or has an inaccurate voltmeter.

The PIR light will not necessarily be burning 2 x 6.9 watts during the day as these lights incorporate a daylight sensor which will probably disable the PIRs during daylight hours. The standby power consumption should be detailed on the booklet which came with the light.

Zahc

Geez, I thought I was a geek; I'm saving this thread to show the beloved to prove that I'm only a pretend geek!!
Very informative though.

P= VR, everyone knows that. V=IR, so........

Oh never mind:rotfl:

Zahc