Rectification is the process of converting an alternating current (AC) waveform into a direct current (DC) waveform, which flows in only one direction/03%3A_Diode_Applications/3.2%3A_Rectification). This process is achieved using an electrical device called a rectifier, which can be used in various applications such as DC power supplies and high-voltage direct current power transmission systems. Rectification can also serve in roles other than generating direct current, such as detecting radio signals or detecting the presence of a flame in gas heating systems.

There are different types of rectification, including half-wave rectification, full-wave rectification using a center-tapped secondary, and bridge rectification/03%3A_Diode_Applications/3.2%3A_Rectification). Half-wave rectification and full-wave rectification using a center-tapped secondary produce a peak voltage loss of one diode drop, while bridge rectification has a loss of two diode drops.

In addition to its electrical meaning, rectification can also refer to the act of correcting or making something right. For example, rectification can be used to purify a substance by repeated or fractional distillation.