Automotive Electronics Practice Test

In a series circuit, how is the total circuit resistance determined?

1. By averaging the resistances

2. By summing the resistances

3. By taking the minimum resistance

4. By multiplying the resistances

The correct answer is: By summing the resistances

In a series circuit, the total resistance is determined by summing the resistances of each component connected in the circuit. This is because, in a series configuration, the current flowing through each resistor is the same, and the total resistance encountered by the current is simply the cumulative effect of each individual resistor. Therefore, if you have resistors with different resistance values connected in series, the total resistance can be calculated by adding all their values together. This principle is rooted in Ohm's law and the basic rules governing series circuits. Since the voltage across the entire circuit is shared among the resistors, the total resistance increases as more resistors are added. Thus, the effective resistance can be represented mathematically as R_total = R1 + R2 + R3 + ... + Rn. This sum captures the total opposition to current flow in the circuit, allowing for the correct calculation of total resistance in any series setup. Other methods, such as averaging, taking the minimum, or multiplying resistances would not yield a valid representation of total resistance in a series circuit and are not applicable for this type of electrical configuration.