In a series circuit, the voltage across components does what with respect to the source voltage?

In a series circuit, the voltage across components does what with respect to the source voltage?

• A. They sum to source voltage
• B. Each component gets same voltage
• C. Voltage drops are independent
• D. Voltage drop occurs only across the first component

Answer: (A)

In a series circuit, the same current flows through every component, and the voltages across each component add up to the source voltage. This happens because the energy per unit charge supplied by the source must be dissipated by the components as voltage drops, so the sum of those drops equals the supply voltage (Kirchhoff’s voltage law). The voltage across a component is the current times its resistance, so unless all resistances are identical, the individual voltage drops will differ even though the current is the same. It’s not only the first component that drops voltage, and the drops aren’t independent—they are linked so that their total matches the source.

In a series circuit, the same current flows through every component, and the voltages across each component add up to the source voltage. This happens because the energy per unit charge supplied by the source must be dissipated by the components as voltage drops, so the sum of those drops equals the supply voltage (Kirchhoff’s voltage law). The voltage across a component is the current times its resistance, so unless all resistances are identical, the individual voltage drops will differ even though the current is the same. It’s not only the first component that drops voltage, and the drops aren’t independent—they are linked so that their total matches the source.