web.de z.B. (www.web.de rechts oben) ist kostenlos
GMX, Mymail.ch, mail.ru etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.etc.
Das kommt darauf an, ob die Widerstände in Reihe oder parallel geschaltet sind.
. http://www.phynet.de/e-lehre/der-gesamtwiderstand-eines-stromkreises