Electronics 01
Why 100nF Decoupling Capacitors? The Impedance Math
Why is every decoupling capacitor 100 nF? Impedance plots with ESL and via inductance show what the value really does and when 1 µF is better.
capacitors
Electronics 02
Why Is the RC Time Constant 63%? The Math of 1 − 1/e
63.2% is 1 minus 1/e, the point where an RC curve would have finished if it kept its starting slope. Why e appears, and why 5τ is not always enough.