1. EduRev
EduRev is a highly recommended online resource for studying electrical engineering as an optional subject. It offers a wide range of study materials, including notes, videos, practice questions, and previous year question papers. EduRev has a user-friendly interface and provides comprehensive coverage of the subject.

2. Online Courses
Many renowned universities and educational platforms offer online courses in electrical engineering. These courses are designed and taught by experts in the field and provide in-depth knowledge of various topics. Some platforms like Coursera, edX, and Udemy offer both free and paid courses, allowing learners to choose based on their preferences and budget.

3. YouTube Channels
YouTube is an excellent resource for electrical engineering students. There are several channels dedicated to the subject, offering lectures, tutorials, and demonstrations. Some popular channels include MIT OpenCourseWare, NPTEL, and Learn Engineering. These channels provide high-quality content and are a great supplement to traditional textbooks.

4. Online Forums and Communities
Participating in online forums and communities can be beneficial for electrical engineering students. Platforms like Quora, Stack Exchange, and Reddit have dedicated communities where students and professionals discuss various topics related to electrical engineering. These platforms allow learners to ask questions, seek clarification, and engage in discussions with like-minded individuals.

5. Online Simulators and Virtual Labs
Simulators and virtual labs provide hands-on experience in electrical engineering. Websites like CircuitLab, Multisim Live, and Virtual Experiments offer virtual environments where learners can design and simulate circuits, analyze their behavior, and gain practical insights. These tools enhance understanding and bridge the gap between theory and application.

6. Online Study Groups
Joining online study groups can be a great way to collaborate and learn from fellow electrical engineering students. Platforms like Facebook Groups, WhatsApp Groups, and Telegram Channels have dedicated communities where learners can share study materials, discuss concepts, and support each other throughout their learning journey.

In conclusion, EduRev, online courses, YouTube channels, online forums, online simulators, and virtual labs, as well as online study groups, are some of the recommended online resources for studying electrical engineering as an optional subject. These resources provide comprehensive study materials, interactive learning experiences, and opportunities for collaboration, ultimately enhancing the understanding and knowledge of students.