power and energy (1 Viewer)

[shimmerz_777]

i get voltage, resistance, current, but there are two things im unsure about.

Power? why do we measure stuff in it? what purpose does it serve. is it just on about efficiency or something else? because its made up of the three things above is it really nessesary?

also what unit relates to electrical energy? how do i turn these in to joules or something? thanks

 

[Forbidden.]

i get voltage, resistance, current, but there are two things im unsure about.

Power? why do we measure stuff in it? what purpose does it serve. is it just on about efficiency or something else? because its made up of the three things above is it really nessesary?

also what unit relates to electrical energy? how do i turn these in to joules or something? thanks

Power is the amount of energy converted. It is measured in the SI Units called Watts

Power is calculated by P = VI

We measure POWER because we want to find out the efficency of an appliance, its performance and how much energy is converted.

Energy conversion is when one form of energy is converted into another form of energy. Heaters turn electrical energy into heat energy, lots of it, hence it uses lots of energy to produce lots of power. The electrical company charges you on how much energy is converted (power used).

Yes, the above factors, current, resistance and voltage affect the appliance in many ways.

Energy ? E = VIt

Energy (Joules)= Potential Difference (Volts) x Current (Amps) x Time (seconds)

AS far as I know ...

C'mon, Im sure you learnt this in Preliminary Physics ...

 

[shimmerz_777]

it was so long ago... thanks. the reason y i asked this was in transistors and intergrated circuits, it said the power output was greater than input, and i got a bit unsure with how that was possible