Automotive Electronics Practice Test

What does Technician A say about the voltage drops in a series circuit compared to the source voltage?

1. They should equal the source voltage

2. They fluctuate based on load

3. They have no relation to the source voltage

4. They increase with more resistors

The correct answer is: They should equal the source voltage

In a series circuit, the total voltage drop across all components must equal the source voltage, according to Kirchhoff's Voltage Law. This law states that the sum of the electrical potential differences (voltage) around any closed circuit is zero. Therefore, when multiple components—such as resistors—are connected in series, the voltage across each component will add up to equal the total supplied voltage from the source. As a result, if you measure the voltage drop across each individual component in the circuit and sum these values, they should collectively match the source voltage. This is a fundamental concept in understanding how series circuits operate and is crucial for diagnosing electrical issues in automotive systems where resistive loads are common. In contrast, other choices either describe situations that do not apply to series circuits or misinterpret the relationship between voltage, load, and components. Thus, recognizing that the voltage drops in a series circuit should equal the source voltage is essential for both theoretical understanding and practical applications in automotive electronics.