the Boella effect

In researching my April 26 article about measuring ultra low currents I saw some 1967 ADI documents that referred to the Boella effect. Intrigued, I looked up the real scoop and found it here and here. Reposting:

“Mario Boella (Genova, Italy, 31/01/1905 - Loranzè Canavese (TO), Italy, 16/02/1989) developed new devices and performed researches in the fields of time and frequency measurements. He is also known for having discovered the effect [Boella effect] of parasitic capacitances in a resistor, which causes a decay of resistance with frequency. If properly combined with the skin effect, which causes a resistance increase with frequency it leads to resistors whose value is very stable with frequency”

And there was even more cool stuff I learned about voltage coefficients on resistors– yes, at really low levels, the applied voltage (even DC) will change the resistance a tiny bit. Analog is fun because analog is hard.