7812 pdf datasheet

The LM7812 series of three terminal regulators is available
with several fixed output voltages making them useful in a
wide range of applications. One of these is local on card
regulation, eliminating the distribution problems associated
with single point regulation. The voltages available allow
these regulators to be used in logic systems, instrumentation,
HiFi, and other solid state electronic equipment. Although
designed primarily as fixed voltage regulators these
devices can be used with external components to obtain adjustable
voltages and currents.
The LM78XX series is available in an aluminum TO-3 package
which will allow over 1.0A load current if adequate heat
sinking is provided. Current limiting is included to limit the
peak output current to a safe value. Safe area protection for
the output transistor is provided to limit internal power dissipation.
If internal power dissipation becomes too high for the
heat sinking provided, the thermal shutdown circuit takes
over preventing the IC from overheating.