B4R Tutorial [Hint] HC-05,06 Power supply

Hello all, I read a few posts asking about the power supply requirements of the Bluetooth module. I thought I can put this hint so people can use the right voltage or power supply.
The HC-x comes in two modules, a basic a basic chip and an assembled module.. please see the attached image. The power supply for the basic chip or PCB is 3.3 VDC, while the fully assembled module is powered by regular 5.0 VDC


To add a B4R HINT forum for all contributions that are less than a tutorial like this one.


Licensed User
Longtime User
If I may add to your hint, The bare board is powered by 3,3v but also the TX/RX levels are in this same values, being a one = 3,3v and a zero = 0v.
On the other hand, the bare board assembled in a breakout board, may be powered by a 5V PSU, since on board it has a buck converter (5V to 3,3V), BUT, and there is a BUT, the RX/TX logic still works on a 3,3V levels!!!
You may use a voltage divider created with resistors, or use a level converter!