Tom=E1s =D3 h=C9ilidhe wrote:
> Anyway here's what went on in my head when I was trying to get a grip
> on it:
>     * Power =3D Energy per second
>     * Power is measured in watts, which is joules per second
>     * Power =3D Voltage x Current =3D volts x amperes
>     * 1 ampere =3D 1 coulomb per second
>     * Therefore Power =3D volts * coulombs / seconds
>     * Therefore Energy =3D volts * coulombs

This is all correct.

> Is it possible to take that 1.5 volts, step it up to 5 volts, and make
> it put a steady 25 mA through the resistor?

Yes.  That's what switching power supplies do, in this case a "boost"
converter.  Switchers convert watts at one voltage and current to watts at a
different voltage and current, minus some loss.

>     * I haven't a clue how efficient step-up regulators are, but I'll
> take a wild guess of 95 %, so that would bring the battery current to
> about 87 mA.

Unless you're a expert, and you're not if you have to ask, 70-80% is a
better estimate.


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