Conductor Resistance is usually denoted by letter R, Resistance unit is ohm, abbreviated as ou, notation is Ω (Greece letter, transliterated as pomu m? ga), 1Ω=1V/A. Relatively large units are thousands of Ohm (kΩ), megohm (MΩ) (Meg = million, that is, 1 million).

current basic unit is the ampere, 1 ampere define as: two radical infinitely long parallel straight wires 1 meter apart in a vacuum, with equal constant current, when the force on each meter of wire is 2×10^-7N, the current on each wire is 1 ampere.

voltage The main unit in the International System of Units is the volt (V), abbreviated as the volt, denoted by notation V. [1]1 volt is tantamount to 1 joule of work for every 1 coulomb charge on the voltage table, i.e. 1 V = 1 J/C. Strong voltage is commonly used in kilovolts (KV), and small voltage units can be millivolts (mV) microvolts (μv).