This is a DC-DC step down power converter module based on the AMS1117 integrated circuit.  This module is meant to reduce 5VDC nominal input voltage to 3.3V.  It will deliver a consistent output of 3.3V up to 800mA.  This module uses a shared negative pin for both 3.3V and 5V.  This voltage regulator module is easy to use and durable.  It is protected against short circuits and overloads.  Built-in thermal protection circuitry will shut down the regulator should the temperature exceed 165 degrees C.