The L78L05ACUTR is a linear voltage regulator made by STMicroelectronics. It is a surface-mount, SOT89-style component and operates over an ambient temperature range of 0°C to 125°C. It provides a fixed 5V output at a maximum current of 0.1 ampere (100 mA). It is used to provide a constant and stable 5V reference source that is well regulated over a wide range of input voltages and temperatures.