HP Netzteil DC Kabel Polarität?

That only knows HP, because every manufacturer does what he wants. There will be a plus pole and a minus pole. You can easily find out the polarity with a multimeter. Simply set to DC voltage measurement and if a minus is displayed before the voltage value, the cables are wrong. If not black from multimeter to minus and red from multimeter to plus. The third cable is often either a data line that reads out a code stored in the power supply to ensure that it is an original power supply part of HP. If this is not the case, or the code does not fit, in many cases the laptop does not start or is not loaded. Another reason is the recognition of the power of the connected power supply. There are notebook manufacturers that offer different power supply types with different power. Sometimes only one resistor is connected between this line and ground, whose value is read out in the notebook and has exactly the same function. With HP it is often a data line, so the power supplies are also so expensive.

I found different polarities and color codings for many HP notebooks. Say, they don’t have a standard for it. The best way to get you a cheap multimeter in the construction market or on Amazon etc. to find out the polarity. A useful instrument, which still has many other uses;)