This modules can be used to convert AC to DC. The most common AC supply voltages are 5, 12v, 15v, 16v, 18v and 24v, these modules will handle all these voltages, and convert them into DC up to a max of 4 Amps. The output voltage will depend on the input voltage from the transformer. There is typically a voltage drop of 2 volts through the circuit.
There is a LED indicator to show there is output power.