Logic IC's from transistors...

[JimB]

Thinking about gates, is it possible to make a schmitt inverter with transistors although i doubt you can...

There was a time before integrated circuits when all there was to build gates and schmidts and etc were discrete transistors.

There was also a time before transistors when all there was to build gates and schmidts and etc were thermionic valves (electron toobs to those of a USA persuasion ).

There was life before integrated circuits, just bigger, more expensive, used more power and ran hotter.

JimB

 

[4pyros]

thermionic valves (electron toobs to those of a USA persuasion ).

Just "Tubes" Please

 

[eTech]

There was a time before integrated circuits when all there was to build gates and schmidts and etc were discrete transistors.

There was also a time before transistors when all there was to build gates and schmidts and etc were thermionic valves (electron toobs to those of a USA persuasion ).

There was life before integrated circuits, just bigger, more expensive, used more power and ran hotter.

JimB

And before those there were relays for logic....

eT

 

[4pyros]

And before those there were relays for logic....

eT

and before that??

 

[Reloadron]

Tubes? I saw one once in a museum I think.

Think about ENIAC (Electronic Numerical Integrator And Computer).

ENIAC contained 17,468 vacuum tubes, 7,200 crystal diodes, 1,500 relays, 70,000 resistors, 10,000 capacitors and around 5 million hand-soldered joints. It weighed more than 30 short tons (27 t), was roughly 8 by 3 by 100 feet (2.4 m × 0.9 m × 30 m), took up 1800 square feet (167 m2), and consumed 150 kW of power. Just imagine heating 17,468 vacuum tubes, think about the power consumed by the filaments alone. When I taught at a Navy school in San Diego it was common practice on a cold morning to fire up all the scopes (Tektronix 545B Models) and HP 524 Counters just to get some heat in the classroom.

Ron

 

[eTech]

and before that??

Before that humans were too busy avoiding predators to think about logic gates...

eT

 

[atferrari]

Tubes? I saw one once in a museum I think.

Think about ENIAC (Electronic Numerical Integrator And Computer).

ENIAC contained 17,468 vacuum tubes, 7,200 crystal diodes, 1,500 relays, 70,000 resistors, 10,000 capacitors and around 5 million hand-soldered joints. It weighed more than 30 short tons (27 t), was roughly 8 by 3 by 100 feet (2.4 m × 0.9 m × 30 m), took up 1800 square feet (167 m2), and consumed 150 kW of power. Just imagine heating 17,468 vacuum tubes, think about the power consumed by the filaments alone. When I taught at a Navy school in San Diego it was common practice on a cold morning to fire up all the scopes (Tektronix 545B Models) and HP 524 Counters just to get some heat in the classroom.

Ron

I recall seeing in the Web, a picture of ENIAC and someone pushing a small cart said to carry the tubes eventually used to replace the failed ones.

The "Loadicator", analog computer used to calculate several parameters as trim, drafts, displacement, etc, in one of my last bulk carriers (vessels), was implemented with opamps and made the Deck Office the warmest room on board after the engine room. Now that is software in a dedicated PC.

 

[cowboybob]

... When I taught at a Navy school in San Diego it was common practice on a cold morning to fire up all the scopes (Tektronix 545B Models) and HP 524 Counters just to get some heat in the classroom.

Ron

Those Tek 545s (and the HPs) were everywhere (late '60's - early '70's) at my end of the US on the Fast Attacks we supported (off a Tender). I was a CalTech (1598) and those poor ******* "bubble heads" had to tote them from interior sub - brow - pier - tender after brow - 4 decks up (under heliport) and into our lab. And then, of course, then take'm back home.

As I recall, they weighed about 45 or 50lbs each.

And yes, they put off some very respectable heat (as did most of the gear).

My current DSO might (might) get to room temp plus 10 degrees...

 

[atferrari]

from interior sub - brow - pier - tender after brow - 4 decks up (under heliport)

Brow: first time I see that word. Warships only, I guess.

 

[DerStrom8]

Personally I'd recommend using MOSFETs instead of BJTs for logic. BJTs are current-controlled, whereas FETs are voltage-controlled. You can use either one, but FETs use less power and are more precise. That's the difference between TTL and CMOS though, so I suppose you can take your pick. The attached file is a powerpoint from a professor at the university where I work, and it has some schematics showing how FETs are used to create logic gates. Hope it helps!

Regards,
Matt

 

[Reloadron]

Personally I'd recommend using MOSFETs instead of BJTs for logic. BJTs are current-controlled, whereas FETs are voltage-controlled. You can use either one, but FETs use less power and are more precise. That's the difference between TTL and CMOS though, so I suppose you can take your pick. The attached file is a powerpoint from a professor at the university where I work, and it has some schematics showing how FETs are used to create logic gates. Hope it helps!

Regards,
Matt

I agree Matt and a good white paper. I think we have focused on basic transistors for simplicity but use of a FET offers many benefits over standard old transistors. While much of this is amusing and interesting I haven't seen transistor designed gates used in actual circuits for a good number of years.

Ron

 

[Reloadron]

Brow: first time I see that word. Warships only, I guess.

No, the Brow is generally center ship on any ship where passengers can board the ship or disembark (leave the ship). It is just a nautical term that applies to all ships, not limited to warships. Another common term is the Gangway.

Cowboybob's reference was to a US Navy submarine which yes, is a war ship and due to the nature and construction of a submarine it is a difficult and demanding task to get anything on and off a submarine. Especially the smaller submarines like the Fast Attack subs. Loading supplies is always a challenging task and loading a torpedo is a real challenge.

Ron

 

[tvtech]

And I sit here thinking about the wonderful Members here...

ETO is not like other Sites out there where one person tries to be smarter than the rest...here we talk about stuff. We don't argue because we all respect each other. We get along together and that is why ETO is what ETO is.....it's like now and again....I go overboard....and lo and behold someone here will reel me in and sit me down and tell me to take it easy...it could be either Mick, or maybe Matt or maybe Killivolt or any other of the regulars here...

I tell you it's crazy stuff. We all kind of look after each other.....and you Guys will find this hard to believe.....but here goes anyway...

Nobody...but nobody must ever speak crap about any of you behind your back on another Forum...no go for me.

I either say it straight in the face or shut up. Hey, not the most subtle person around...but I tell it like it is. And that makes me what I am.

I look at it this way: the Truth or nothing. I am as subtle as a ball of the proverbial shite....but at least I am honest about it

Well that's me. You all know me by now.

And that is my little tale. Stay well all of you.

Regards...
you know who

 

[atferrari]

No, the Brow is generally center ship on any ship where passengers can board the ship or disembark (leave the ship). It is just a nautical term that applies to all ships, not limited to warships. Another common term is the Gangway.

Cowboybob's reference was to a US Navy submarine which yes, is a war ship and due to the nature and construction of a submarine it is a difficult and demanding task to get anything on and off a submarine. Especially the smaller submarines like the Fast Attack subs. Loading supplies is always a challenging task and loading a torpedo is a real challenge.

Ron

For me, common expressions are gangway or accommodation ladder but never brow.

Gracias Ron.

 

[4pyros]

Personally I'd recommend using MOSFETs instead of BJTs for logic. BJTs are current-controlled, whereas FETs are voltage-controlled. You can use either one, but FETs use less power and are more precise. That's the difference between TTL and CMOS though, so I suppose you can take your pick. The attached file is a powerpoint from a professor at the university where I work, and it has some schematics showing how FETs are used to create logic gates. Hope it helps!

Regards,
Matt

Thanks Matt. Saved in the bowels of my PC.

 

[DerStrom8]

Thanks Matt.

Anytime!