L7812ABV STMicroelectronics 12V Linear Voltage Regulator (TO-220-3)

A huge range of relays, fans, older peripheral interfaces, and analog circuitry run on 12V, and this regulator is the standard way to derive a clean 12V rail from a higher battery or adapter voltage. The ABV precision grade holds tighter output tolerance than the standard-grade CV part, which is worth the small price difference when a circuit downstream is sensitive to exactly how close to 12V the rail actually sits. It accepts 19V to 35V on the input and delivers up to 1.5A on the regulated 12V output, in the same TO-220 package the whole 78xx family shares, so it heatsinks the same way the 5V and 15V versions do.