How do you determine the polarity of an AC voltage source?

To determine the polarity of an AC voltage source, identifying the waveform's phase and reference point is essential. In an AC circuit, voltage oscillates between positive and negative values, and its polarity is not fixed as it is in DC circuits.

The phase of the AC waveform indicates which part of the cycle the waveform is currently at, and the reference point, often the zero-crossing point, helps to establish whether the voltage is currently positive or negative relative to that point. Tools like an oscilloscope can visually display these phases, allowing for a clear understanding of the voltage's behavior over time. This method provides a reliable and accurate means of assessing the AC voltage characteristics.

Other methods, such as using a multimeter, might show voltage readings but won't clarify the AC waveform's polarity without specific context regarding the phase. Measuring resistance or referencing a circuit diagram can be helpful for general circuit analysis, but they do not directly relate to determining polarity in an alternating current scenario.