What does the formula ET = E1 + E2 + ... EN calculate?

The formula ET = E1 + E2 + ... + EN is used to calculate the total voltage in a series circuit. In a series circuit, the total voltage (ET) is the sum of the individual voltages (E1, E2, ..., EN) across each element or component connected in the circuit. This means that if you have multiple voltage sources or drops within a circuit, you can find the overall voltage by simply adding them together.

This is based on the fundamental principle that in a series configuration, the voltage across each component accumulates to form the total voltage. Understanding this concept is crucial for analyzing voltage in electrical circuits, especially when dealing with series connections where components share the same current.