7812

7812 refers to a fixed positive voltage regulator in the 78xx family, designed to provide a stable +12 V output from a higher input voltage. It is a three-terminal device that acts as a linear regulator, dropping excess input voltage to maintain a constant output under varying load and input conditions. The part is widely used in DC power supplies for electronics, microcontrollers, and other circuits requiring a regulated 12-volt rail.

Pinout and packaging commonly follow the TO-220 form factor. For the typical orientation with the front of the package facing you and leads pointing downward, the pins are arranged left to right as input, ground, and output; the metal tab is usually connected to ground. Some variants and packages may use different pinouts, so the datasheet should be consulted for exact details.

Electrical characteristics are given for a typical device: input voltage up to about 35 V, maximum output current around 1 A (depending on device and heat sinking), and a dropout voltage near 2 V at full load. The output voltage tolerance is generally around a few percent at room temperature, and the regulator draws a small quiescent current. Because it is a linear regulator, efficiency drops as the difference between input and output voltages increases, and heat dissipation is a key design consideration.

External capacitors improve stability and transient response: a small input bypass capacitor (about 0.33 µF) and a small output capacitor (about 0.1 µF) are commonly recommended, placed close to the regulator. Larger electrolytics may be used to smooth ripple and support transient loads.

Protections include current limiting and thermal shutdown to prevent damage. The 7812 is often identified in variants such as LM7812, 7812CV, or 7812A, and is available in multiple packages from many manufacturers.