I have released the next video of the test series of ferrite cores. This is the M-088 nanoper core from Magnetec. It is a filter core with extraordinary performance values at higher power values. It shows in self triggered mode like the Joule Thief or the LED driver circuit very low frequency response based on the high permeability of the core. This is causing issues with my current probes because they measure accurate at frequency from 150 Hz upwards. However, at higher power and frequency they work well. This is so far the best performing core with a COP of over 2. In my next test I will compare it to a transformer core the same size.
The video is on the same page under Movies and the direct link for Gold members is here.