Calculating Power Dissipation in a Circuit

JSGandora

If I ran over a problem asking for power supplied by a non-ideal battery, or a battery with an internal resistance. Do I account for the internal resistance when I calculate the power dissipation? Or do I just account for the loads (finding the total resistance excluding the internal resistance of the battery and then multiplying it by the current squared to get the power) excluding the internal resistance?

Studiot

Surely that depends on the question?

The power dissipated in the internal series resistance is the reason batteries become warm/hot when you draw power from them.
But this power is unavailable to the circuit. The power in the circuit is the product of the load current and the voltage across the load.

JSGandora

Oh, I see now. Thanks for your clear response!

Studiot

go well

JSGandora

Hmm? What do you mean by "go well"?

Also, just to make sure, if the questions stated "What is the power supplied by battery D?", then we only account for the power dissipated by the load, correct?

Studiot

Go well is an English phrase wishing you good fortune in the future.

I would take the question
"What is the power supplied by battery D?"

To mean the power drawn by the load.

I think the key word is 'supplied'
The internal dissipation wasted in heating the battery is not supplied to anything.

I would expect a question including the internally dissipated power to read something like

'Find the total power expended by the battery' or 'Find the total power developed by the battery'.

JSGandora

Thank you, it's very clear to me now. Go well to you too!