This post explains for the Regulator.
The Part Number is 7812A, MC7812A.
The function of this semiconductor is 12V, Voltage Regulator.
The package is TO-220, D2Pak Type
Manufacturer: ON Semiconductor
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7812A is 1A, 12V, Positive Voltage Regulator. A voltage regulator is an electronic device that is used to maintain a constant voltage level, regardless of changes in load or input voltage. This helps to ensure that the voltage supplied to a device remains within the acceptable range, even under varying conditions such as changes in temperature or load.
These voltage regulators are monolithic integrated circuits designed as fixed−voltage regulators for a wide variety of applications including local, on−card regulation. These regulators employ internal current limiting, thermal shutdown, and safe−area compensation. With adequate heatsinking they can deliver output currents in excess of 1.0 A. Although designed primarily as a fixed voltage regulator, these devices can be used with external components to obtain adjustable voltages and currents.
• Output Current in Excess of 1.0 A
• No External Components Required
• Internal Thermal Overload Protection
• Internal Short Circuit Current Limiting
• Output Transistor Safe−Area Compensation
• Output Voltage Offered in 2% and 4% Tolerance
• NCV Prefix for Automotive and Other Applications Requiring Site and Control Changes
• Pb−Free Packages are Available