Editing Resistor (section)

===Ohm's law===
{{Main article|Ohm's law}}

An ''ideal resistor'' (i.e. a resistance without [[Electrical reactance|reactance]]) obeys [[Ohm's law]]:

<math display="block">V=I \cdot R.</math>

Ohm's law states that the [[voltage]] (<math>V</math>) across a resistor is proportional to the [[Electric current|current]] (<math>I</math>) passing through it, where the constant of proportionality is the resistance (<math>R</math>). For example, if a 300-[[ohm]] resistor is attached across the terminals of a 12-volt battery, then a current of 12 / 300 = 0.04 [[ampere]]s flows through that resistor.

The [[ohm]] (symbol: [[Ω]]) is the [[International System of Units|SI]] unit of [[electrical resistance]], named after [[Georg Simon Ohm]]. An ohm is equivalent to a [[volt]] per [[ampere]]. Since resistors are specified and manufactured over a very large range of values, the derived units of milliohm (1&nbsp;mΩ = 10<sup>−3</sup>&nbsp;Ω), kilohm (1&nbsp;kΩ = 10<sup>3</sup>&nbsp;Ω), and megohm (1&nbsp;MΩ = 10<sup>6</sup>&nbsp;Ω) are also in common usage.<ref>{{cite book | author=[[American Radio Relay League]] (ARRL) | title =ARRL Handbook for Radio Communications | publisher =American Radio Relay League |isbn=978-1-62595-139-7 | date=2021 | edition =98| chapter = Fundamental Theory—Circuits and Components}}</ref><ref name=arrl1968>{{cite book | url=https://archive.org/details/arrl_1968_handbook |editor=Doug DeMaw | title =Radio Amateurs Handbook | publisher =American Radio Relay League |date=1968 | edition=45 |chapter = Electrical Laws and Circuits —Resistance}}</ref>{{rp|p.20}}