Seven Segment Displays for old-timers

[Ivan Seeking]

I had to LOL when I saw this.

http://upload.wikimedia.org/wikipedia/commons/3/3f/Incandescent_light_seven-segment_display.jpg

I remember those but had forgotten all about them.

 

[DaveC426913]

I bow in relative neophytic deference, Old One.

 

[Ivan Seeking]

I bow in relative neophytic deference, Old One.

Too much of a pup for that one? :rofl:

 

[Danger]

I believe that they were called 'Nixie Tubes'. Totally blew me away when they came out.

 

[mgb_phys]

No I think that is a seven segment Neon version of a LED
A nixie tube has the numbers 0-9 as separate shapes behind each other.

 

[binzing]

It's not really that outdated, the one aged feature about it is that its in a tube. And I think this should be in electronics?

 

[Danger]

No I think that is a seven segment Neon version of a LED
A nixie tube has the numbers 0-9 as separate shapes behind each other.

I stand corrected.

 

[dst]

I don't understand why it didn't occur to anyone to make those (older) tubes with segmented neon tubes as in the OP?

 

[turbo]

Now I feel old. The only thing glowing in my electronic stuff when I was a kid (aside from the tubes) was maybe a cat's-eye on the front.

 

[Ivan Seeking]

Now I feel old. The only thing glowing in my electronic stuff when I was a kid (aside from the tubes) was maybe a cat's-eye on the front.

My dad and uncle were both electronics freaks who had great stashes of electronic supplies. I also hung out with a couple of hams in the neighborhood who for some reason tolerated the presense of a pesky kid. So I spent many hours playing with 60s era electronics. I didn't start to play with digital electronics until about 1975.

 

[mgb_phys]

I don't understand why it didn't occur to anyone to make those (older) tubes with segmented neon tubes as in the OP?

If you mean why didn't they make a 7segment neon?
The computing power to calculate which segments of a 7seg to turn on for a particular number is too great, it requires dozens of gates which is a lot if you are building them from vacuum tubes.
The advantage of Nixie tubes is that you have 10 wires, each representing a single number, whch is very easier to wire to a counter - even a mechanical one.


A Nixie tube http://upload.wikimedia.org/wikiped...1210-operating.jpg/200px-ZM1210-operating.jpg

 

[waht]

I'm sure that in 50 years, someone's grandkid will post a holographic rendering of an LCD display on public interaction forums with some laughs.

 

[DaveC426913]

If you mean why didn't they make a 7segment neon?
The computing power to calculate which segments of a 7seg to turn on for a particular number is too great, it requires dozens of gates which is a lot if you are building them from vacuum tubes.
The advantage of Nixie tubes is that you have 10 wires, each representing a single number, whch is very easier to wire to a counter - even a mechanical one.

I see these on TV shows and wondreed why they built them this way. I'd always speculated that, if each number could be lit separately from each other (unlike 7 segment LEDs), there would be less delay, and thus more accurate timing. Or something.

 

[jim mcnamara]

Now I feel old. The only thing glowing in my electronic stuff when I was a kid (aside from the tubes) was maybe a cat's-eye on the front.

Oh phooey. Electronics meant the nylon covered wires running all over the basement thru white ceramic insulators. And spider webs. Switches were round knobs that you simply rotated any direction to go to the opposite switch state. No worries about little paddles pointing up or down - or if the switch was off or on, you just kept twiddling knobs 'til you got to the desired state of affairs, or blew a cigar-sized fuse. Whichever came first.

The cabinet radio with the analog dial was the family centerpiece. Socially and electronically. I never did like that wimp - Orphan Annie. And her dumb dog, too...

 

[dst]

If you mean why didn't they make a 7segment neon?
The computing power to calculate which segments of a 7seg to turn on for a particular number is too great, it requires dozens of gates which is a lot if you are building them from vacuum tubes.
The advantage of Nixie tubes is that you have 10 wires, each representing a single number, whch is very easier to wire to a counter - even a mechanical one.


A Nixie tube http://upload.wikimedia.org/wikiped...1210-operating.jpg/200px-ZM1210-operating.jpg

I was thinking that if you have a set of connections to turn on a specific combination of cells, then you can, through a bit of wiring, have 1 terminal for each number and a ground. So you would reduce it to the complexity of the average Nixie tube. You won't need any computation, just predefined numbers. The number 1 would need just 2 left segments, 2 would require power to so and so segments, etc - these can be hardwired quite easily, and I do believe I did something similar with LEDs as a child.

 

[mgb_phys]

This is what a 7 segment display chip does - but you need logic gates to do it. Otherwise how would you avoid having the 3,5,7,8,9 inputs all shorted together because they are all connected to the top element?

You can do it with a 16 element * 8bit memory or, since not all combinations of output are used, more efficently by a logic network.