The d.c. resistance of a conductor is its ohmic value, which is dependent on the specific characteristics of the material and on the geometric dimensions. Resistance is measured in Ohm, symbol Ω (Omega). A resistor has the value R = 1 Ω when the applied voltage U = 1 Volt enables for a current flow of I = 1 ampere (Ohm’s law R = U / I, in honor of Georg Simon Ohm).