Final answer:
The total resistance in a circuit with series resistors is the sum of all resistances. For parallel resistors, it is calculated with a specific equation based on the reciprocal of their resistances. The total resistance for combined series and parallel circuits involves finding the parallel equivalent resistance first and adding it to the series resistances.
Step-by-step explanation:
To calculate the total resistance in a circuit, we first need to identify whether the resistors are arranged in series or in parallel. For resistors in series, the total resistance (Rtot) is simply the sum of all the individual resistances. Thus, Rtot = R₁ + R₂ + R₃, where R₁, R₂, and R₃ are the values of the individual resistors.
In the case of resistors in parallel, the total resistance is calculated using the formula 1/Rtot = 1/R₁ + 1/R₂ + ... + 1/Rn for n resistors. For two resistors in parallel, the equation simplifies to Rtot = (R₁ ⋅ R₂) / (R₁ + R₂).
If the circuit has both series and parallel components, we first calculate the equivalent resistance of parallel components, then add it to the series resistances. For example, if R₂ and R₃ are in parallel, first find their equivalent resistance Rp and then add it to R₁ to find the total resistance.