What does it mean to understand something, especially something one finds really hard  to understand? I take it that “understanding” must necessarily fall far short of “complete understanding,” which seems superhuman. More modestly, what does it mean to make a...

Faraday’s galvanometer and modern galvanometers operate on the same principle: the tendency of a magnetic element to align itself in the direction of the surrounding magnetic field. But Faraday’s instrument and modern ones function very differently. Modern...

Although the topic of my talk is alternating current, I’d like us to begin with a few experiments using direct current. Direct current is what batteries produce, but we shall obtain it from one of our venerable “EFB” power supplies.