I'm trying to use a AMS1117 3.3V to deliver 3.3V from a 5V input.
Case 2. 5V input supplied directly from micro usb output.
When the voltage regulator is not attached, the micro usb outputs 5V. When it is attached, this output goes down to 4.9V and the regulator outputs 4.2V.
Can anyone help me understand what is going on? The 5V output from the module passes through a chip with an underlined 4 on it. What does this chip do?