This is a terrible article. All that text, pictures and diagrams to poorly illustrated Kirchhoff’s Voltage Law, which wasn't even mentioned at all. The conclusi

This is a terrible article. All that text, pictures and diagrams to poorly illustrated Kirchhoff’s Voltage Law, which wasn't even mentioned at all. The conclusion of 150ohms of internal resistance for a 9V battery is totally off too, doesn't help he's using resistors with 5% accuracy.