I need to know the polarity of the LG sta-u35wr charger to see if it is compatible with my tablet, since the ac charger broke but the same amps and watts are produced by the USB charger as the ac adapter.
If it's made for charging that device then the polarity will be correct. Chargers and devices often have a symbol to show polarity, it's like the letter C with a dot in the middle and a line coming out from the dot leading to a +ve or -ve sign to tell you the polarity of the centre contact. Sometimes info is written or moulded on very small letters so it's hard to read. Another way is to use a multimeter and compare polarity with a working charger for the same device. You don't have to know which lead is which, just touch the probes the same way round on both (most chargers are +ve centre connection so I'd suggest putting the RED probe in the centre and the black on the outer connection. If the plugs show the same polarity then they are both suitable to use. A digital multimeter may have a -ve sign before the voltage reading, but if both plugs show negative they are the same. If one shows a -ve sign but the other doesn't then it's no-go. Meters don't usually show a +ve sign.
