Broken rectifier? Outputs both DC and AC

Thread Starter


Joined Nov 15, 2019
So I want to make a DC power source from my moped so I can charge my phone, but my rectifier from the coil puts out DC and AC on my multimeter. Am I doing something wrong or is it broken?


Joined Oct 2, 2009
Welcome to AAC!

You have your meter set to AC range and it still shows voltage even though you think that the supply is DC only. Correct?

The AC scale is meant for measuring LINE voltage such as 120VAC @ 60Hz or 230VAC @ 50Hz depending on your country. You cannot use the AC range when measuring DC voltages. There is nothing wrong with your meter. That is simply how the meter is designed when measuring AC.


Joined Nov 15, 2019
Which ped you got? Might want to check out a moped specific forum for flywheel output and adding accessories. You can pick up a cheap lawnmower regulator rectifier for like $8 and wire it to convert AC to DC


Joined Mar 30, 2015
no I don't but I have this voltage regulator which converts it into 12V. On the output I connected this car 12V- 5V usb adapter thing. When I connect my phone to it, it shows the charging symbol and then it immediately disappears.
I doubt that there are many switching regulators that could generate a stable 12V under the conditions you have (as I understand them).

With a single rectifier, this is what you'd have:
The input drops to 0V. Without a filter cap it's not going to work very well.