Hello everyone,(adsbygoogle = window.adsbygoogle || []).push({});

I'm trying to teach myself basic circuit design from an EE textbook, but I'm starting to think myself in circles here. I have no trouble with the basic algebra, but the logic behind the formulas is giving me trouble.

The thing I'm most confused about right now is the relation of current to power:

1) [itex]P=I^2R[/itex]

2) and [itex]P = VI[/itex]

From these, it's clear that if the current stays constant and the voltage increases, power will increase proportionally... but I just can't wrap my head aroundwhythat's so.

Let's say we have a 12V battery connected to a resistor such that it draws 1A. We have another setup that uses a 24V battery and a stronger resistor, such that the current is similarly 1A. The circuit draws the same current but uses double the power. How can that be?

Can someone please help me understand what's going on here?

**Physics Forums - The Fusion of Science and Community**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# How is it that power can vary if the current stays constant?

Loading...

Similar Threads - power vary current | Date |
---|---|

Can self induction increase power consumption? | Sunday at 7:18 AM |

Internal resistance of a cell varying with power drawn | Mar 22, 2017 |

Charging EV with varying input power | Apr 27, 2016 |

Constant Power to a Varying Load | Jul 10, 2010 |

Maintain constant Power in varying load | Sep 21, 2007 |

**Physics Forums - The Fusion of Science and Community**