. 2014 Sep 15;24(3):4671. doi: 10.4081/ejtm.2014.4671
This article is distributed under the terms of the Creative Commons Attribution Noncommercial License (by-nc 3.0) which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.
Fig 9.
The electrode impedance for 20 mA vs. frequency.