Nodemcu powering with 5.2v and 2A? I bought a this voltage regulator . DC-DC 5v 8A voltage regulator. ıts supported 8-35V input voltage . And i want to use this with 12v power supply.
But i searched on the internet . Nodemcu max amp is 800mA. This device can provide 2A per usb output if i will plug the nodemcu with usb cable this what happen ? Does it burn ? How can i drop the amps ?  i want to use other 3 usb output with other devices sensors and screen .
Generally, we specify DC power supplies as constant voltage sources.  In order to do this, power supplies deliver more or less current as demanded by the load in an attempt to keep the voltage constant regardless of the load.  

When a constant voltage DC power supply specifies a maximum current, it is saying the power supply can only maintain the specified voltage while the current demand is less than the specified maximum current.  

To be clear, unless you need a constant current power supply, a power supply should be picked based on the required constant voltage.  And the capacity of that power supply, usually measured in Amps, should exceed the maximum combined current demand of all connected devices (loads).