This post explains for the semiconductor 78L33.
The Part Number is 78L33.
The function of this semiconductor is Positive voltage regulators.
Manufacturers : STMicroelectronics
The L78L series of three-terminal positive regulators employ internal current limiting and thermal shutdown, making them essentially indestructible. If adequate heat-sink is provided, they can deliver up to 100 mA output current. They are intended as fixed voltage regulators in a wide range of applications including local or oncard regulation for elimination of noise and distribution problems associated with single-point regulation. In addition, they can be used with power pass elements to make high-current
voltage regulators. The L78L series used as Zener diode/resistor combination replacement, offers e improvement along with lower quiescent current and lower noise.
1. Output current up to 100 mA
2. Output voltages of 3.3 V thermal overload protection
3. Short-circuit protection
4. No external components are required