power for rf transmitter and reciever

I am designing appliance control project by using rf transmitter and reciever by using 433Mhz module.but can I give power from power adaptor(5v/2Amp) to a circuit?I am confusing because rf transmitter and reciever require very little current.

Any current lower than power supply capability is no problem. This only means that the power supply will not be fully loaded. You can use a 5V, 0.5A power supply, too.
DC voltage is important to keep at 5V. If you decide to use a battery, e.g. 9V, a voltage regulator must be used to get 5 V.

Also there are some wall-mount 5V power adapters (DCDC based, without transformer) where if they don't see a minimum load, the DCDC is not starting (power saving mode) and will be no voltage at the output.