If an engineer stops learning, their knowledge can become obsolete in just a few years. This means engineers need to be lifelong learners.

Luckily, there are many free resources available to learn new engineering principles, migrate to new fields, and keep up with the latest technology solutions and best design practices.

While Signal Integrity Journal should be the first stop to stay up to date on new developments or brush up on basics, there are many great resources out there that are useful tools for continued learning. Here is a baker's dozen selection of websites with high-value content related to SI, PI, and EMI, all with extensive resources that are free of charge. 

• SIJ University: In particular, check out the extensive collection of webinars and technical papers. Become a subscriber today.
• Teledyne LeCroy Webinars: Full disclosure, I am a fellow with Teledyne LeCroy and produced some of these videos. That said, I still recommend all of them.
• Keysight Learn Center: An extensive collection of more than 10,000 papers, videos, and courses.
• Samtec Signal Integrity Center for Excellence: This includes more than just the famous Geek Speak video series. An extensive collection of experts sharing their knowledge.
• Simberian Application Notes, Papers & Videos with Yuriy Shlepnev: A collection of over 100 application notes and videos on how interconnects work from my go-to expert on electromagnetics of interconnects.
• Rohde and Schwarz Knowledge Center: A collection of hundreds of webinars and videos about measurement and analysis for SI/PI and EMI applications.
• Analog Devices EngineerZone: A collection of application notes and videos using a variety of electronic components.
• TI Precision Labs: Video training on a variety of power electronics and amplifier applications
• Monolithic Power Systems Learning Center: A useful collection of webinars and videos about power systems and EMI.
• Copper Mountain Webinars: A collection of webinars on beginner and advanced VNA and S-parameter topics.
• Altium Student Lab: An extensive list of courses to learn Altium and to learn PCB design.
• Learn EMC: A collection of application notes and some videos from a world expert in EMC. Take the online quizzes to test yourself.
• Coursera: Extensive collection of courses on electrical engineering and power electronics. Most are free to view. (Please note that there is a fee to get credit for these courses.)