scope guard

Jerobeam Fenderson shows how to draw a mushroom on an oscilloscope in XY mode using stereo audio, then animates it by modulating with a larger wave. Pd and Max4Live patches are provided.

A roughly 90-minute film of John Dobson building a Dobsonian telescope step by step, including hand-grinding the mirror.

A 1953 US Navy training film on the basic mechanisms in fire control computers: shafts, gears, cams and differentials. It shows how these mechanical parts compute ship and target firing solutions.

Dave Jones builds the Evil Mad Scientist discrete-component 555 timer kit, then tests it and explains the internal circuitry of the 555 at transistor level. He finishes with scope waveforms.