White black blue for communication validate adapter and battery power it is best you use a multimeter to check.
White wire black wire blue wire laptop charger.
The black wire will be your hot wire and your whites are neutral depending on your switch setup you can wire nut the blacks together with an extra piece of wire coming from the wire nut to connect the hot to the light as well as the same method with your white wires.
Set the meter to read voltage.
So i connected the white wire to the shilding wire and red wire to the core wire of the old 90w adapter s plug.
If this is in reference to the many dell machines using the 3 pole 7 4mm barrel connector the 3rd wire goes to a 1 wire serial chip that the laptop reads to find out which wattage power adapter it is connected to so that it can limit its power dra.
Turn the meter on.
In another forum someone identified the sensor wire and left it out in the connection.
Well the white is the sense and that will make laptop know that the right charger is connected the open sheild cable is the power when the big thick sheild is ground but you cant use 2 wire power instead you can use any other 3 wire board useing the same config in other power the sense can be blue like hp or red or grey its simple if you have a multimeter.
The one on mine has blue white and black and they are.
The first adapter the one that broke has three wires black white and red going out which then connect to the laptop charger pin.
Identify the black positive wire on a ceiling light fixture.
While powered the charger found red wire 19vdc white wire 0vdc black wire in the center pin for feedback to the board.
The second adapter however has three wires going out.
Turn the charger on.
If the display shows a positive number black is negative b w is positive.
I have read that an extra wire is used as some kind of a sensor.
Carefully touch the meter probes black to the black wire red to the b w wire.
After connecting the wires make sure to test the voltage on the plug before inserting to the laptop or you might risk damaging your laptop.