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darwinbeing / HPServerPSUHack

HP HSTNS-PL11/PL30/PL42 Server PSU Modification for Vehicle Flashing and Programming
MIT License
40 stars 13 forks source link

Decrease output voltage for HSTNS-PL11 #1

Closed gotofbi closed 1 year ago

gotofbi commented 1 year ago

Hi,

If I want to decrease voltage to 10.2v, how can I achieve this? When I used the calculator, it showed negative resistor which doesn't make sense ;)

darwinbeing commented 1 year ago

WolframAlpha Solver Output 10.2V

The approach of using resistors in parallel is only effective for increasing output voltage; it cannot be employed to decrease the output voltage. To achieve a reduction in the output voltage, resistor substitution is necessary. Based on the given formula: $$R{11}=1411, R{12}=2.25$$ For obtaining an output voltage of 10.2V, the utilization of parallel resistors is no longer viable. Instead, it is required to substitute resistor R123 with a 411-ohm resistor, and replace resistor R102 with a 2.25 k-ohm resistor(OVP) or patch the firmware.