Electronics 01
Why Phone Charging Slows After 80%: The CC-CV Curve
Fast charging fills a phone from 0 to 70% at full current, then a fixed voltage limit makes the current taper. The physics, the plating risk and the math.
Electronics
Electronics 02
Why Is Electricity Transmitted at High Voltage? The Math
Why is electricity transmitted at high voltage? We work the I²R loss for a real 345 kV line, show why 1,100 kV is about the ceiling, and when HVDC wins.
Electronics 03
Why Is AC Power 60 Hz (or 50 Hz)? The Real Tradeoffs
60 Hz came from an 1890 Westinghouse study of engines, lamps and transformers, not Tesla. The physics of transformer size, skin effect and line length.
Electronics 04
LiPo C Rating Explained: Current, Sag and Real Limits
A 5000 mAh 50C LiPo is rated for 250 A, but at 3 milliohms per cell that current sags each cell by 0.75 V. What the C rating means and how to check it.
Electronics 05
Why Is Coax 50 Ohms? The Loss and Power Math
Why is coax 50 ohms? Loss is lowest at 77 Ω, power peaks at 30 Ω, voltage at 60 Ω. Plots of all three, the polyethylene twist, and why TV uses 75 Ω.
Electronics 06
Why Don't Birds Get Electrocuted on Power Lines?
A bird on a live wire feels about 4 millivolts and 4 microamps. We work the numbers, bust the 'not grounded' myth, and show when birds really do die.