I bought this Arduino starter kit from Amazon. The problem I have now is that the voltage supplied by the breadboard adapter seems to change every time I turn it off and on. And not by small amounts either. The voltage swings between 6.5 and 4.8V. Am I doing anything wrong or is that power supply just bad? The changing voltage messes up all my Sensor readings which is bad. So is there a better power supply or any way to fix this one?