I enjoyed this demo of how exactly neural nets work:

I liked the interactive demo. I feel like I have a better intuitive understanding of weight and bias mean.

I took a machine learning course during my undergrad, and it was focused more on formulas and implementing machine learning algorithms. I felt that it didn’t really give me a fully intuitive understanding of how these algorithms really worked. I managed to implement the algorithms in Matlab, and I was able to step through them and look at the result of each iteration, but it always seemed a bit too complex to grasp.

This article, with its interactive elements, walks you through how sigmoid functions work and what they actually do.