Which wire is negative on this PC fan? - Electrical Engineering Stack Exchange

I just got this PC fan and it has a 3 pin connector, I know the wire with the white stripe is positive but how can I find out which of the other two wires are negative? If you can't see the photo

pcb - Can we ground all the nets in a printed circuit board? - Electrical Engineering Stack Exchange

CDMALL AC Motor Speed Controller，AC Electronic Fan Speed Controller Variable Adjuster for Hydroponics Inline Duct Exhaust Ceiling Fans with 6' Long 120V 15A Cord : Tools & Home Improvement

Energies, Free Full-Text

Electro-optic spatial light modulator from an engineered organic layer

Connect a 4-pin connector to power supply - Electrical Engineering Stack Exchange

arduino - Replacing BD139 for TIP122 - Cooler speed control circuit - Electrical Engineering Stack Exchange

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Combine multiple power supplies with shared negative - Electrical Engineering Stack Exchange

mosfet - high side switch using NMOS - Electrical Engineering Stack Exchange