Final answer:
The equivalent resistance is a single value that replaces a combination of resistors without changing the overall electrical characteristics. In series, resistances add up, while in parallel, the equivalent resistance is calculated using reciprocals. This helps in determining the circuit's current flow with Ohm's law.
Step-by-step explanation:
The equivalent resistance calculated from nominal R values refers to a single resistance value that can replace a combination of several resistors in a circuit, conserving the same electrical characteristics. When you calculate the equivalent resistance of resistors connected in series, the resistances add up directly. The formula is:
Requiv(series) = R1 + R2 + R3 + ... + Rn
For resistors connected in parallel, the equivalent resistance is found by the reciprocal of the sum of the reciprocals of each resistance. The formula is:
1/Requiv(parallel) = 1/R1 + 1/R2 + 1/R3 + ... + 1/Rn
Then, Requiv(parallel) is the reciprocal of the result. In both cases, using Ohm's law, knowing the equivalent resistance helps us to calculate the current flowing through the circuit given a certain voltage.