EEweb.com's online scientific calculator is free. EEWeb.com also has some other online tools for Engineers and hobbyists.
Visit Scienctific Calculator : Online Scientific Calculator
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Visit German version: EEWeb Germany - Electronics and electrical engineering forum - EEWeb.de
Description : EEWEb Germany is an electronics and electrical engineering community. It offers news, forum, electrical and electronic design articles and other related resources in one place. Electrical and electronic design articles including RF design, analog design, embedded design, PCB design, test and measure.