quick question - pd

[Kane2oo2]

hi
if u have say something that is rated at 36W and draws a constant current of 3A over 600seconds how would you work out the p.d across it?

i got 0.02v .... but errr doesnt look right lol

 

[spuffock]

Divide the watts by the amps, thats 12v . The time does not affect the equation.

 

[Kane2oo2]

lol
i just got it now i was gunna reply but you did first....i was doing IVT instead of P/I for some strange reason

thanks anyway

dont spose you know how to calculate number of electrons flowing for that time period?

 

[spuffock]

you multiply the amps by the seconds to give you the charge in coulombs,
then you divide that by the charge on an electron, which I can't remember off the top of my head.
Ah,yes,its1.6022*10^-19.
that,ll be about 11.2345*10^20 electrons

 

[Painandsuffering]

wow!!

All I have to say about this is thats a lot of electrons! lol.