What about Philips? At Philips Matlab 1] one guy boasted that their computers at one time where better than IBM's. Small wonder because they made the tubes themselves. 100 linear equation in 100 unknowns in a matter of minutes!
They stopped making semiconductor memories at about 1 megabit, but their BC547 and BC557 are going strong till this day.
1] I worked on FORTRAN programs there for simulation of magnetic and electronic circuits in the '80's-- Albert van der Horst, UTRECHT,THE NETHERLANDS Economic growth -- being exponential -- ultimately falters. albert@spe&ar&c.xs4all.nl &=n http://home.hccnet.nl/a.w.m.van.der.horst
One of my first books on electronics was the 1968 edition of RCA Transistor Manual. It contained a lot of useful information in addition to the raw individual transistor data
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I still use them myself where GP low-power BJTs are needed. IIRC the BC54x and 55x series started out as metal can BC10x and 17x respectively. In today's money, their cost in the early '70s would be at least 50 times that of a BC5xx now.
I remember an episode of Mr. Wizard (remember him?) where he wired up a fla shlight to the speaker cable from a record player, then pointed the flashli ght at an open film projector and the audio played through the projector sp eakers. Up until that point I never knew how they added the audio to a fil m.
lashlight to the speaker cable from a record player, then pointed the flash light at an open film projector and the audio played through the projector speakers. Up until that point I never knew how they added the audio to a f ilm.
The sound track is variable width or variable density. The latter gives not so good sound.
NT
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flashlight to the speaker cable from a record player, then pointed the fla shlight at an open film projector and the audio played through the projecto r speakers. Up until that point I never knew how they added the audio to a film.
ot so good sound.
As long as we are reminiscing, does anyone know where the RCA CA3089 FM de tector IC was developed?
I thought it was in Bridgewater NJ in the big building along Rt202 at Town e center next to the Wegmens across from Fisher Scientific?
Is that true?
I feel sad every time I see that building.
m
RCA was giant in semiconductors. So was GE. And Sylvania. And Raytheon.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
I find common cathode works well. :)
-- Rick C
Late 70s (I think) - the vacuum photocell used to extract the soundtrack in a local cinema hall had degraded badly, but replacement of non-consumer parts were difficult to get here. So I thought of making a solid-state substitute.
I still had some AC125s and AC128s (European TO-1 Ge alloy-junction types) but I thought the spectral response and bandwidth of Si types would be more suitable. So I used a TO-5 Si BJT after cutting off the top and covering it again with transparent tape.
I had to make other modifications - the mounting, for one. And I inserted a simple preamp before it was plugged in to the tube amp. But more critical was the light from the exciter lamp after it had passed through the film's sound track. I changed it from variable width to variable intensity by diffusing it.
My biggest worry was that there would be excessive loss of high frequencies, but the result was quite acceptable. The original system was never hi-fi anyway. They used it that way until they closed down in the early 90s.
a e
ow
a flashlight to the speaker cable from a record player, then pointed the fl ashlight at an open film projector and the audio played through the project or speakers. Up until that point I never knew how they added the audio to a film.
not so good sound.
Increasing heater voltage is good to get emissions up too. And anode if nec essary.
NT
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