Most helpful critical review
17 of 17 people found the following review helpful
Avoid avoid avoid!
on 8 September 2014
I used it for a while and noticed that when I had my phone connected to the stereo in the car as well as this, a lot of electronic noise would come over the speakers. This was partly engine noise caused by the alternator and partly a high frequency switching sound coming from the power supply.
I put my oscilloscope on there to take a look at the voltage it was outputting and it is all over the place! It spikes as high as 10 volts (it is supposed to output 5 volts for USB) and dips down to zero volts once every switching cycle (4,000 times per second). The switching frequency is right in the middle of human speech intelligibility, meaning your ears are most sensitive to it. That is why the noise on the stereo is so invasive and annoying.
In conclusion, it will annoy you, and probably damage your phone given how high the voltage goes sometimes. As soon as I saw how bad the output was I threw it away.