Vaihtovirtajännitteille

Vaihtovirtajännitteille refers to alternating current voltages in Finnish. Unlike direct current (DC), where the voltage polarity remains constant, alternating current (AC) voltage periodically reverses its direction. This means the voltage rises to a positive peak, falls through zero, reaches a negative peak, and then returns to zero, repeating this cycle continuously. The frequency of this change, measured in Hertz (Hz), indicates how many complete cycles occur per second. Common mains electricity frequencies are 50 Hz or 60 Hz.

The sinusoidal waveform is the most common representation of AC voltage, characterized by its amplitude, frequency, and phase. The amplitude represents the maximum voltage value reached during a cycle. The instantaneous voltage at any point in time can be calculated using a mathematical formula that depends on these parameters. AC voltages are crucial for power transmission over long distances due to the ease with which their voltage levels can be transformed using transformers, allowing for efficient step-up for transmission and step-down for domestic use. Many electronic devices utilize AC voltage, which is then converted to DC for their internal operation.