> JOOI, does anyone know when Panaplex 7-segment displays started going the > way of the dodo, to be replaced with LED displays (and, on the back of > that, what were the advantages of a Panaplex-type display over an LED one?)
It would appear that in the early 1970s LEDs were very expensive. I have been looking at the HP5930x HPIB units and in many cases the status indicators (power on, listening, etc) are filament bulbs + driver transistors. I can think of no advantage to using a filament bulb in this application other than possibly cost. The 59304, which has a Panaplex display and therefore the HV supply to drive it, uses neon bulbs (NE2 sort of thing) as status indicators. -tony
