How to get 5V from phone charger

Members

I have used an old usb cable to supply a board with 5V. When I plug this into my PC usb I get 5V. When I plug this into my phone charger I receive only 2.2V.

I snipped the end of an old charger cable and used the following wires: Red-Supply & Green-ground & Brown- not connected & White- not connected.

Any ideas on why this is happening?

Thanks

Some phone chargers will only put out a lower voltage until they see a load on the output.

BJHenry:
Some phone chargers will only put out a lower voltage until they see a load on the output.

And some phone chargers output unfiltered DC pulses. What did you use to measure the voltage?

Paul

fnb111:
Members

I have used an old usb cable to supply a board with 5V. When I plug this into my PC usb I get 5V. When I plug this into my phone charger I receive only 2.2V.

I snipped the end of an old charger cable and used the following wires: Red-Supply & Green-ground & Brown- not connected & White- not connected.

Any ideas on why this is happening?

Thanks

Supply wires should be red and black. white and green are data wires. Your "brown" is likely the negative
supply.

Hi All,
I think Paul is correct. I have seen this with
another type of battery charger. The battery
acts like a filter capacitor to the half-wave
rectified current being supplied by the charger.
A half-wave rectified voltage has an average
value of 0.45 times the peak voltage* supplied.
The battery does not care what the waveform
is like as long as the peak is higher than its
present terminal voltage. (*for sine waves)
Herb