This is one of the TTL IC types.
Part Number: 7805, LM7805
Function: 5V, Voltage Regulator
Package: TO-220 Type
Manufacturer: National Semiconductor
This post explains for the Voltage Regulator.
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Description
This 7805 series of fixed-voltage integrated-circuit voltage regulators is designed for a wide range of applications. These applications include on-card regulation for elimination of noise and distribution problems associated with single-point regulation. Each of these regulators can deliver up to 1.5 A of output current. The internal current-limiting and thermal-shutdown features of these regulators essentially make them immune to overload.
In addition to use as fixed-voltage regulators, these devices can be used with external components to obtain adjustable output voltages and currents, and also can be used as the power-pass element in precision regulators.
7805 Pinout
Features
1. Output current in excess of 1A
2. Internal thermal overload protection
3. No external components required
4. Output transistor safe area protection
5. Internal short circuit current limit
Schematic
Other data sheets are available within the file: 7812, 7815, LM7805, LM7812, LM7815