What is Ohm's law?

Answer

I proportional to V for a fixed temperature.

Ohm's Law defines the relationships between voltage (E), current (I), resistance (R) and power (P). One ohm is the resistance value through which one volt will maintain a current of one ampere. One volt of voltage moving one ampere of current is "creating" one watt of power (the so-called volt-amp).

( I ) Current is what flows in a wire or conductor like water flowing through a pipe. Current flows through a conductor from points in a circuit that are more negative to points in that circuit that are more positive (electron current flow). Current is measured in amperes or amps (A).

( E ) Voltage is the difference in electrical potential between two points in a circuit. It's the push or (electrical) pressure behind current flow through a circuit. It is what causes current flow, and it is measured in volts (V).

( R ) Resistance is a measure of a material's inability to carry current. It determines how much current will flow through a component for a given voltage. Resistors are used to control voltage and current levels. A very high resistance allows a small amount of current to flow for a given voltage. A very low resistance allows a large amount of current to flow for that same voltage. Resistance is measured in ohms (upper case omega).

( P ) Power is the amount "work" being done in a circuit. It is current times the voltage level across a given portion of the circuit, and it is measured in watts (W).

Here's how it works:

E = I x R (voltage equals current times resistance)

P = I x E (power equals current times voltage)

There are variations on the theme, and here are all the expressions of Ohm's law:

E = I x R, I = E / R, R = E / I

P = I x E, P = I² x R, P = E² / R

Here's the translation:

Voltage = current times resistance; current = voltage divided by resistance; resistance = voltage divided by current.

Power = current times voltage; power equals current squared times resistance; power equals voltage squared divided by resistance.

All the equations say the same thing. It's just a question of what you have to work with or how you wish to express what you have.

As an example, we sometimes talk about I² R losses. As you might recognize, I² R is an expression of power. We say, "I squared R," and we mean P = I² times R. The I² R losses in a wire are the resistance losses in a conductor due to the resistance of the conductor and the current flowing through it. We sometimes talk about I squared R losses regarding the losses to resistance in long distance transmission lines. Even at extremely high voltage, there are losses in the line due to the resistance. (And we intentionally jack up the voltage in transmission lines to minimize losses like this. The only limit is our ability to insulate the several hundred thousand volts from the towers from which we hang the transmission lines.)

First answer by ID1126215445. Last edit by Leosks134. Contributor trust: 1 [recommend contributor]. Question popularity: 108 [recommend question]