ESA Certified Alarm Technician Practice Exam

If two resistors are connected in series, what happens to the total resistance?

1. It decreases

2. It doubles

3. It is equal to the sum of the individual resistances

4. It remains unchanged

The correct answer is: It is equal to the sum of the individual resistances

When two resistors are connected in series, the total resistance in the circuit is calculated by adding the individual resistances together. This is based on the principle that in a series circuit, the current that flows through each resistor is the same, and the voltage across each resistor can be different depending on its resistance value. The formula for total resistance (R_total) in series is: R_total = R1 + R2 + ... + Rn Where R1, R2, ..., Rn are the resistances of the individual resistors connected in series. This means the total resistance is simply the sum of the resistances of the individual resistors, which explains why the correct answer states that the total resistance is equal to the sum of the individual resistances. Understanding this concept is critical for technicians as it aids in calculating how resistors will influence the overall behavior of electrical circuits, which is fundamental in alarm systems and many other electronic applications.