GPS is one of the few consumer technologies that would fail within minutes if Einstein had been wrong. We walk the physics of fixing your position from four orbiting atomic clocks, why four and not three, the special- and general-relativistic corrections baked into every receiver, how the C/A code lets a phone hear a signal weaker than thermal noise, and why your first fix is slow and the next one is instant.
Physics
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How GPS Computes Your Position -
How a Transistor Actually Works: From Sand to Switch The physics under every computing device, from semiconductor doping and the depletion region through MOSFETs and CMOS, to the leakage crises that drove FinFETs, GAAFETs, and the relentless geometry of Moore's Law.
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Signal Integrity: Why Your Cat6 Cable Is Twisted The transmission-line physics under structured cabling: characteristic impedance, differential signaling, crosstalk, skin effect, and why the exact geometry of a copper wire determines whether your 10-gigabit link trains or refuses to come up.
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The Thermodynamics of Cooling Your Rack Every watt your homelab consumes becomes heat, and heat physics — not marketing — dictates whether your equipment lives or throttles. From Q = m·Cp·ΔT and CFM math to heatsink fin geometry, airflow management, liquid cooling, and PUE thinking applied at home: a working engineer's guide to the thermodynamics of the rack.
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Why GPS Needs General Relativity GPS clocks run fast by 38 microseconds every day due to relativistic effects — special relativity slows them, general relativity speeds them up, and without compensating for both your position drifts 10 kilometers further wrong each day.