Circuit Jam helps a bit for practice: https://play.google.com/store/apps/details?id=com.circuitjam
Also, stack exchange: https://electronics.stackexchange.com/questions?sort=votes
Circuit Jam helps a bit for practice: https://play.google.com/store/apps/details?id=com.circuitjam
Also, stack exchange: https://electronics.stackexchange.com/questions?sort=votes