Filaments
Rectifier and dual triode vacuum tubes on the job since 1963. The glowing filaments heat a cathode sleeve that boils off electrons that are then captured by a charged plate. For the rectifier, they can only go in one direction, and AC is converted to DC. For the dual triode, control grids fashioned like a finely wound fence are interposed whereby a small change on the grids cause a large change on the plates, and amplification is achieved.
Zoom to explore.
Canon FD 100mm f/4 macro, taken at f/11, long exposure on tripod.
Filaments
Rectifier and dual triode vacuum tubes on the job since 1963. The glowing filaments heat a cathode sleeve that boils off electrons that are then captured by a charged plate. For the rectifier, they can only go in one direction, and AC is converted to DC. For the dual triode, control grids fashioned like a finely wound fence are interposed whereby a small change on the grids cause a large change on the plates, and amplification is achieved.
Zoom to explore.
Canon FD 100mm f/4 macro, taken at f/11, long exposure on tripod.