closeup of old germanium point-contact diode in sealed glass tube

16x9 70s 80s anode background blur board bokeh cable cathode circuit closeup component contact copy crystal design detector development device diode disposal electrical electrode electronic electrotechnics electrotechnology engineering ewaste filament focus germanium glass industrial industry inside insulated insulation junction macro melted metal nobody nopeople obsolete old package part point radio receiver recycling red retro sealed selective semiconductor sleeve space tech technical technology transparent tube tungsten two vacuum vintage waste welded white wire yellow