Electric current

Electrical resistance

The electrical resistance of an electrical conductor is a measure of the difficulty of passing an electric current through a substance. It explains the relationship between voltage (amount of electrical pressure) and the current (flow of electricity). With more resistance in a circuit, less electricity will flow through the circuit. The inverse of resistance is conductance, a measure not much used. All objects have some resistance, except superconductors.

Resistance, discovered by Georg Simon Ohm in 1827, is the ratio between voltage and current. Ohm's law said that the voltage between any two points in a conductor changes directly as the current between the two points, given the temperature remains the same. He described it with the equation:
{\displaystyle R={\frac {V}{I}}}R=V/I
which models the ratio, where:
R {\textstyle R} is the resistance of the object, measured in ohms (Ω)
V {\textstyle V} is the voltage across the object, measured in volts (V)
I {\textstyle I} is the current going through the object, measured in amperes (A)
Elektr qarshiligi
Elektr o'tkazgichning elektr qarshiligi - bu modda orqali elektr tokini o'tkazish qiyinligi. U kuchlanish (elektr bosimi miqdori) va oqim (elektr oqimi) o'rtasidagi munosabatni tushuntiradi. Zanjirdagi qarshilik ko'proq bo'lsa, kontaktlarning zanglashiga olib keladigan elektr energiyasi kamroq bo'ladi. Qarshilikning teskarisi - o'tkazuvchanlik, ko'p ishlatilmaydigan o'lchov. Supero'tkazuvchilardan tashqari barcha jismlar biroz qarshilikka ega.
1827 yilda Georg Simon Om tomonidan kashf etilgan qarshilik kuchlanish va oqim o'rtasidagi nisbatdir. Om qonuni shuni ko'rsatdiki, harorat bir xil bo'lib qolsa, o'tkazgichning har qanday ikkita nuqtasi orasidagi kuchlanish to'g'ridan-to'g'ri ikkita nuqta orasidagi oqim sifatida o'zgaradi. U buni tenglama bilan tavsifladi:
R=V/I
nisbati qaysi modellar, bu erda:
R - om (Ω) bilan o'lchanadigan ob'ektning qarshiligi
V - ob'ektdagi kuchlanish, voltda o'lchanadi (V)
I - ob'ektdan o'tadigan oqim, amper (A) bilan o'lchanadi.