What does a resistor value of “NOM” mean?
$begingroup$
On this schematic of part of the Apollo Guidance Computer (found here), some resistors have a value of "NOM."
According to this question, "NOM" stands for "nominal" when it's found in a datasheet, but this isn't a datasheet and I don't see how "nominal" would make sense here.
resistors schematics terminology
asked yesterday
MaxpmMaxpm
357312
$endgroup$
|
show 2 more comments
$begingroup$
On this schematic of part of the Apollo Guidance Computer (found here), some resistors have a value of "NOM."
According to this question, "NOM" stands for "nominal" when it's found in a datasheet, but this isn't a datasheet and I don't see how "nominal" would make sense here.
resistors schematics terminology
asked yesterday
MaxpmMaxpm
357312
$endgroup$
28
$begingroup$
It means the schematic software is very hungry and has started eating your circuit. I see further down it has started naming other components after Family Guy characters, so it must be going mad with hunger.
$endgroup$
– Benjamin Wharton
yesterday
1
$begingroup$
Now or NOM @BenjaminWharton that would have to be NOM NOM NOM.
$endgroup$
– StainlessSteelRat
yesterday
3
$begingroup$
It's old enough the schematic software might be called Dave or Fran
$endgroup$
– Journeyman Geek
yesterday
3
$begingroup$
@StainlessSteelRat Shouldn't that be Ohm Nom Nom?
$endgroup$
– fluffy
yesterday
2
$begingroup$
Intentional use of Fran actually. There's always been women in tech who're forgotten. It's entirely plausible the schematics or parts of them were done by women.
$endgroup$
– Journeyman Geek
19 hours ago
|
show 2 more comments
$begingroup$
On this schematic of part of the Apollo Guidance Computer (found here), some resistors have a value of "NOM."
According to this question, "NOM" stands for "nominal" when it's found in a datasheet, but this isn't a datasheet and I don't see how "nominal" would make sense here.
resistors schematics terminology
asked yesterday
MaxpmMaxpm
357312
$endgroup$
On this schematic of part of the Apollo Guidance Computer (found here), some resistors have a value of "NOM."
According to this question, "NOM" stands for "nominal" when it's found in a datasheet, but this isn't a datasheet and I don't see how "nominal" would make sense here.
resistors schematics terminology
resistors schematics terminology
asked yesterday
MaxpmMaxpm
357312
asked yesterday
MaxpmMaxpm
357312
edited 20 hours ago
Maxpm
asked yesterday
MaxpmMaxpm
357312
asked yesterday
MaxpmMaxpm
357312
asked yesterday
MaxpmMaxpm
357312
357312
28
$begingroup$
It means the schematic software is very hungry and has started eating your circuit. I see further down it has started naming other components after Family Guy characters, so it must be going mad with hunger.
$endgroup$
– Benjamin Wharton
yesterday
1
$begingroup$
Now or NOM @BenjaminWharton that would have to be NOM NOM NOM.
$endgroup$
– StainlessSteelRat
yesterday
3
$begingroup$
It's old enough the schematic software might be called Dave or Fran
$endgroup$
– Journeyman Geek
yesterday
3
$begingroup$
@StainlessSteelRat Shouldn't that be Ohm Nom Nom?
$endgroup$
– fluffy
yesterday
2
$begingroup$
Intentional use of Fran actually. There's always been women in tech who're forgotten. It's entirely plausible the schematics or parts of them were done by women.
$endgroup$
– Journeyman Geek
19 hours ago
|
show 2 more comments
28
$begingroup$
It means the schematic software is very hungry and has started eating your circuit. I see further down it has started naming other components after Family Guy characters, so it must be going mad with hunger.
$endgroup$
– Benjamin Wharton
yesterday
1
$begingroup$
Now or NOM @BenjaminWharton that would have to be NOM NOM NOM.
$endgroup$
– StainlessSteelRat
yesterday
3
$begingroup$
It's old enough the schematic software might be called Dave or Fran
$endgroup$
– Journeyman Geek
yesterday
3
$begingroup$
@StainlessSteelRat Shouldn't that be Ohm Nom Nom?
$endgroup$
– fluffy
yesterday
2
$begingroup$
Intentional use of Fran actually. There's always been women in tech who're forgotten. It's entirely plausible the schematics or parts of them were done by women.
$endgroup$
– Journeyman Geek
19 hours ago
28
28
$begingroup$
It means the schematic software is very hungry and has started eating your circuit. I see further down it has started naming other components after Family Guy characters, so it must be going mad with hunger.
$endgroup$
– Benjamin Wharton
yesterday
$begingroup$
It means the schematic software is very hungry and has started eating your circuit. I see further down it has started naming other components after Family Guy characters, so it must be going mad with hunger.
$endgroup$
– Benjamin Wharton
yesterday
1
1
$begingroup$
Now or NOM @BenjaminWharton that would have to be NOM NOM NOM.
$endgroup$
– StainlessSteelRat
yesterday
$begingroup$
Now or NOM @BenjaminWharton that would have to be NOM NOM NOM.
$endgroup$
– StainlessSteelRat
yesterday
3
3
$begingroup$
It's old enough the schematic software might be called Dave or Fran
$endgroup$
– Journeyman Geek
yesterday
$begingroup$
It's old enough the schematic software might be called Dave or Fran
$endgroup$
– Journeyman Geek
yesterday
3
3
$begingroup$
@StainlessSteelRat Shouldn't that be Ohm Nom Nom?
$endgroup$
– fluffy
yesterday
$begingroup$
@StainlessSteelRat Shouldn't that be Ohm Nom Nom?
$endgroup$
– fluffy
yesterday
2
2
$begingroup$
Intentional use of Fran actually. There's always been women in tech who're forgotten. It's entirely plausible the schematics or parts of them were done by women.
$endgroup$
– Journeyman Geek
19 hours ago
$begingroup$
Intentional use of Fran actually. There's always been women in tech who're forgotten. It's entirely plausible the schematics or parts of them were done by women.
$endgroup$
– Journeyman Geek
19 hours ago
|
show 2 more comments
3 Answers
3
active
oldest
votes
$begingroup$
These were hand drawn and you usually have to check around the first few sheets to understand the syntax.
Check out NASA Drawing 2005904.
NOM means NOMINAL.
As for the NOM values. These refer to the actual part numbers.
R3 and R4 are 22kΩ, 1/2W resistors, Part No 1006760-64.
R1 and R2 2%, 1/4W resistors that are referenced in the table, Part Number 1006750.
Looks like 1006760 is the generic part number for 1/2W resistors and 1006750 are 1/4W resistors. These resistors are in bins and these boards were probably assembled by hand.
With Part No 1006750-XXX referring to different actual resistors for different part lists. Different versions for different iterations of the design. As in 126 is bin 126 in the parts inventory.
Part No 1006750-126 to 1006750-129 are (probably) 1% resistors towards the end of the design period.
So R2 is Part No 1006750-25, which is a 510Ω resistor. Similarly R3 on the sheet you reference is the same part number.
The -XXX has to refer to physical bins in a parts locker. If you look at R3 -18 to -21 go from 270Ω to 360Ω, followed by -22 to -39, which go from 390Ω to 2000Ω. Classic engineer move, we don't know what we need, but we do need resistors, so let's order some of all. If you look up 5% resistors, you can probably figure out -1 to -17.
Similarly there is no reel of resistors. They are not producing thousands's of units, but not individual units either. A batch of 10 to 20 in a clean room manual assembly process. No demand for mass production.
I also support Stilez's answer because words matter. The use of Nominal would correspond to optimum or best case answer. These Tables show the evolution of the design as an engineer or design team made changes based upon some measurements. This design is before there were simulations. It would be interesting to simulate the circuitry to see what impact the changes made to the functionality of the circuit.
Odds are probably good that many different individuals were involved in the drafting and design of different sheets. And that there was probably no space for Tables in the first revisions. As the design evolved, additional sheets or Tables were added as needed. Last entry in Tables was the latest approved change. Easiest way to deal with changes to a hand drawn drawing.
answered yesterday
StainlessSteelRatStainlessSteelRat
3,496619
$endgroup$
4
$begingroup$
I suppose they used "nominal" to mean "you should look up this component by name." It's a usage I haven't seen before, but I guess this is the definitive answer.
$endgroup$
– Maxpm
yesterday
1
$begingroup$
"So R2 is Part No 1006750-25, which is a 510Ω resistor" why is it this value specifically?
$endgroup$
– alex.forencich
20 hours ago
1
$begingroup$
Odds are that bin 25 has that resistor
$endgroup$
– StainlessSteelRat
15 hours ago
1
$begingroup$
@Maxpm It's actually the fully correct use of the word "nominal", it's just that more modern usage (at least in some industries) has skewed towards a corruption which means something closer to "normal/expected" (though the corruption itself certainly already existed at the time).
$endgroup$
– Lightness Races in Orbit
6 hours ago
add a comment |
$begingroup$
The notes in the bottom left of the schematic tell you to "select R3, R7 and R14 per applicable PS from appropriate chart", so "NOM" indicates to look in the tables.
As of yet, I have no idea what to do exactly with the numbers in the appropriate tables, and neither do I have any idea what "PS" means.
I'm a bit in the mist about the exact etymology of "NOM", but it cold be "nomogram", despite some tables giving the values instead of graphs. Maybe it's "Notice of Modification"?
answered yesterday
zebonautzebonaut
16k14490
$endgroup$
2
$begingroup$
That “interpret schematic in accordance standard prescribed by MIL D-70327” is probably where the answer lies.
$endgroup$
– winny
yesterday
1
$begingroup$
"PS" could be "parts"?
$endgroup$
– jochen
12 hours ago
$begingroup$
as in per applicable parts from appropriate chart.
$endgroup$
– StainlessSteelRat
11 hours ago
$begingroup$
PS usually means Post Script – ie the table of values is an addendum to the schematic. Given the words 'applicable' and 'appropriate', I'd guess that different tables might be applicable for different scenarios, e.g. different revisions, or calibrations?
$endgroup$
– Dan W
11 hours ago
$begingroup$
I would guess that the people drawing the schematic knew about what the right value should be, but expected that it might need to be refined through experimentation. If the original draftsman expected that 1K should work, but it turned out that 1.5K was required, it would be necessary to ensure that all copies of the schematic that showed a 1K value were corrected or destroyed. Having to reprint schematics for such a change would have been much more expensive than saying "look at the latest version of XX table for the latest value".
$endgroup$
– supercat
10 hours ago
add a comment |
$begingroup$
Nominal is basically used to mean "roughly" or "as stated", or "trade description". But there's a second related meaning which is something like "some small or user-decided (but unspecified) amount/type", and is probably what's meant here. And based on that, is a third meaning, of "some acceptable value", specifically used in space technology.
Meaning "roughly" or "as stated":
You'll see the same word used for many components which aren't sized precisely. For example if you bought some wood or steel for commercial purposes its length might be described as "3m nominal", meaning its about 3m and will do the job, but could be 3m, or 3.02m or something.
- "item of nominal size, nailed at nominal distances _(diagram last page)"
- "PIR (infra red) detector with nominal range (1st para)"
- Aluminium alloys described in terms of nominal compositions
Description of "nominal dimension", on Science Direct: "Parts and components are given nominal dimensions but are allowed to vary within a band of tolerances. Similarly, machine speeds are usually nominal speeds but are frequently allowed to vary slightly within an assigned band of tolerance and so forth."
- Wikipedia entry
- (Note also, in some cases nominal is used to mean a specific type or standard, such as nominal pipe size. But that is clearly not what's meant here.)
Meaning "some small or user-decided (but unspecified) amount/type"
This is a less common usage of the term, as in "leave a nominal air gap" for ventilation. Sorry for poor quality links, I've seen this used in manufacturer documents but can't find examples right now.
- pistonheads forum, "nominal air gap" (2nd post)
- pistonheads forum, "nominal wall design" (9th post)
Dictionary definitions related specifically to space technology:
"Informal (chiefly in the context of space travel): functioning normally or acceptably."
Its not quite the same usage, but perhaps as its in the same field, this was a usage adopted in NASA design, beyond being used to describe the status of a system in operation?
answered 21 hours ago
StilezStilez
1286
$endgroup$
1
$begingroup$
I can't see this being very helpful in context of this question, especially with the StainlessSteelRat's answer showing it has little to do with "roughness". Although one could appreciate getting a wider picture of what it could mean elsewhere.
$endgroup$
– Richard the Spacecat
21 hours ago
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Hopefully expanded and fixed now
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– Stilez
21 hours ago
$begingroup$
I believe it does have some bearing because the design is evolving.
$endgroup$
– StainlessSteelRat
14 hours ago
add a comment |
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3 Answers
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$begingroup$
These were hand drawn and you usually have to check around the first few sheets to understand the syntax.
Check out NASA Drawing 2005904.
NOM means NOMINAL.
As for the NOM values. These refer to the actual part numbers.
R3 and R4 are 22kΩ, 1/2W resistors, Part No 1006760-64.
R1 and R2 2%, 1/4W resistors that are referenced in the table, Part Number 1006750.
Looks like 1006760 is the generic part number for 1/2W resistors and 1006750 are 1/4W resistors. These resistors are in bins and these boards were probably assembled by hand.
With Part No 1006750-XXX referring to different actual resistors for different part lists. Different versions for different iterations of the design. As in 126 is bin 126 in the parts inventory.
Part No 1006750-126 to 1006750-129 are (probably) 1% resistors towards the end of the design period.
So R2 is Part No 1006750-25, which is a 510Ω resistor. Similarly R3 on the sheet you reference is the same part number.
The -XXX has to refer to physical bins in a parts locker. If you look at R3 -18 to -21 go from 270Ω to 360Ω, followed by -22 to -39, which go from 390Ω to 2000Ω. Classic engineer move, we don't know what we need, but we do need resistors, so let's order some of all. If you look up 5% resistors, you can probably figure out -1 to -17.
Similarly there is no reel of resistors. They are not producing thousands's of units, but not individual units either. A batch of 10 to 20 in a clean room manual assembly process. No demand for mass production.
I also support Stilez's answer because words matter. The use of Nominal would correspond to optimum or best case answer. These Tables show the evolution of the design as an engineer or design team made changes based upon some measurements. This design is before there were simulations. It would be interesting to simulate the circuitry to see what impact the changes made to the functionality of the circuit.
Odds are probably good that many different individuals were involved in the drafting and design of different sheets. And that there was probably no space for Tables in the first revisions. As the design evolved, additional sheets or Tables were added as needed. Last entry in Tables was the latest approved change. Easiest way to deal with changes to a hand drawn drawing.
answered yesterday
StainlessSteelRatStainlessSteelRat
3,496619
$endgroup$
4
$begingroup$
I suppose they used "nominal" to mean "you should look up this component by name." It's a usage I haven't seen before, but I guess this is the definitive answer.
$endgroup$
– Maxpm
yesterday
1
$begingroup$
"So R2 is Part No 1006750-25, which is a 510Ω resistor" why is it this value specifically?
$endgroup$
– alex.forencich
20 hours ago
1
$begingroup$
Odds are that bin 25 has that resistor
$endgroup$
– StainlessSteelRat
15 hours ago
1
$begingroup$
@Maxpm It's actually the fully correct use of the word "nominal", it's just that more modern usage (at least in some industries) has skewed towards a corruption which means something closer to "normal/expected" (though the corruption itself certainly already existed at the time).
$endgroup$
– Lightness Races in Orbit
6 hours ago
add a comment |
$begingroup$
These were hand drawn and you usually have to check around the first few sheets to understand the syntax.
Check out NASA Drawing 2005904.
NOM means NOMINAL.
As for the NOM values. These refer to the actual part numbers.
R3 and R4 are 22kΩ, 1/2W resistors, Part No 1006760-64.
R1 and R2 2%, 1/4W resistors that are referenced in the table, Part Number 1006750.
Looks like 1006760 is the generic part number for 1/2W resistors and 1006750 are 1/4W resistors. These resistors are in bins and these boards were probably assembled by hand.
With Part No 1006750-XXX referring to different actual resistors for different part lists. Different versions for different iterations of the design. As in 126 is bin 126 in the parts inventory.
Part No 1006750-126 to 1006750-129 are (probably) 1% resistors towards the end of the design period.
So R2 is Part No 1006750-25, which is a 510Ω resistor. Similarly R3 on the sheet you reference is the same part number.
The -XXX has to refer to physical bins in a parts locker. If you look at R3 -18 to -21 go from 270Ω to 360Ω, followed by -22 to -39, which go from 390Ω to 2000Ω. Classic engineer move, we don't know what we need, but we do need resistors, so let's order some of all. If you look up 5% resistors, you can probably figure out -1 to -17.
Similarly there is no reel of resistors. They are not producing thousands's of units, but not individual units either. A batch of 10 to 20 in a clean room manual assembly process. No demand for mass production.
I also support Stilez's answer because words matter. The use of Nominal would correspond to optimum or best case answer. These Tables show the evolution of the design as an engineer or design team made changes based upon some measurements. This design is before there were simulations. It would be interesting to simulate the circuitry to see what impact the changes made to the functionality of the circuit.
Odds are probably good that many different individuals were involved in the drafting and design of different sheets. And that there was probably no space for Tables in the first revisions. As the design evolved, additional sheets or Tables were added as needed. Last entry in Tables was the latest approved change. Easiest way to deal with changes to a hand drawn drawing.
answered yesterday
StainlessSteelRatStainlessSteelRat
3,496619
$endgroup$
4
$begingroup$
I suppose they used "nominal" to mean "you should look up this component by name." It's a usage I haven't seen before, but I guess this is the definitive answer.
$endgroup$
– Maxpm
yesterday
1
$begingroup$
"So R2 is Part No 1006750-25, which is a 510Ω resistor" why is it this value specifically?
$endgroup$
– alex.forencich
20 hours ago
1
$begingroup$
Odds are that bin 25 has that resistor
$endgroup$
– StainlessSteelRat
15 hours ago
1
$begingroup$
@Maxpm It's actually the fully correct use of the word "nominal", it's just that more modern usage (at least in some industries) has skewed towards a corruption which means something closer to "normal/expected" (though the corruption itself certainly already existed at the time).
$endgroup$
– Lightness Races in Orbit
6 hours ago
add a comment |
$begingroup$
These were hand drawn and you usually have to check around the first few sheets to understand the syntax.
Check out NASA Drawing 2005904.
NOM means NOMINAL.
As for the NOM values. These refer to the actual part numbers.
R3 and R4 are 22kΩ, 1/2W resistors, Part No 1006760-64.
R1 and R2 2%, 1/4W resistors that are referenced in the table, Part Number 1006750.
Looks like 1006760 is the generic part number for 1/2W resistors and 1006750 are 1/4W resistors. These resistors are in bins and these boards were probably assembled by hand.
With Part No 1006750-XXX referring to different actual resistors for different part lists. Different versions for different iterations of the design. As in 126 is bin 126 in the parts inventory.
Part No 1006750-126 to 1006750-129 are (probably) 1% resistors towards the end of the design period.
So R2 is Part No 1006750-25, which is a 510Ω resistor. Similarly R3 on the sheet you reference is the same part number.
The -XXX has to refer to physical bins in a parts locker. If you look at R3 -18 to -21 go from 270Ω to 360Ω, followed by -22 to -39, which go from 390Ω to 2000Ω. Classic engineer move, we don't know what we need, but we do need resistors, so let's order some of all. If you look up 5% resistors, you can probably figure out -1 to -17.
Similarly there is no reel of resistors. They are not producing thousands's of units, but not individual units either. A batch of 10 to 20 in a clean room manual assembly process. No demand for mass production.
I also support Stilez's answer because words matter. The use of Nominal would correspond to optimum or best case answer. These Tables show the evolution of the design as an engineer or design team made changes based upon some measurements. This design is before there were simulations. It would be interesting to simulate the circuitry to see what impact the changes made to the functionality of the circuit.
Odds are probably good that many different individuals were involved in the drafting and design of different sheets. And that there was probably no space for Tables in the first revisions. As the design evolved, additional sheets or Tables were added as needed. Last entry in Tables was the latest approved change. Easiest way to deal with changes to a hand drawn drawing.
answered yesterday
StainlessSteelRatStainlessSteelRat
3,496619
$endgroup$
These were hand drawn and you usually have to check around the first few sheets to understand the syntax.
Check out NASA Drawing 2005904.
NOM means NOMINAL.
As for the NOM values. These refer to the actual part numbers.
R3 and R4 are 22kΩ, 1/2W resistors, Part No 1006760-64.
R1 and R2 2%, 1/4W resistors that are referenced in the table, Part Number 1006750.
Looks like 1006760 is the generic part number for 1/2W resistors and 1006750 are 1/4W resistors. These resistors are in bins and these boards were probably assembled by hand.
With Part No 1006750-XXX referring to different actual resistors for different part lists. Different versions for different iterations of the design. As in 126 is bin 126 in the parts inventory.
Part No 1006750-126 to 1006750-129 are (probably) 1% resistors towards the end of the design period.
So R2 is Part No 1006750-25, which is a 510Ω resistor. Similarly R3 on the sheet you reference is the same part number.
The -XXX has to refer to physical bins in a parts locker. If you look at R3 -18 to -21 go from 270Ω to 360Ω, followed by -22 to -39, which go from 390Ω to 2000Ω. Classic engineer move, we don't know what we need, but we do need resistors, so let's order some of all. If you look up 5% resistors, you can probably figure out -1 to -17.
Similarly there is no reel of resistors. They are not producing thousands's of units, but not individual units either. A batch of 10 to 20 in a clean room manual assembly process. No demand for mass production.
I also support Stilez's answer because words matter. The use of Nominal would correspond to optimum or best case answer. These Tables show the evolution of the design as an engineer or design team made changes based upon some measurements. This design is before there were simulations. It would be interesting to simulate the circuitry to see what impact the changes made to the functionality of the circuit.
Odds are probably good that many different individuals were involved in the drafting and design of different sheets. And that there was probably no space for Tables in the first revisions. As the design evolved, additional sheets or Tables were added as needed. Last entry in Tables was the latest approved change. Easiest way to deal with changes to a hand drawn drawing.
answered yesterday
StainlessSteelRatStainlessSteelRat
3,496619
edited 13 hours ago
answered yesterday
StainlessSteelRatStainlessSteelRat
3,496619
answered yesterday
StainlessSteelRatStainlessSteelRat
3,496619
answered yesterday
StainlessSteelRatStainlessSteelRat
3,496619
3,496619
4
$begingroup$
I suppose they used "nominal" to mean "you should look up this component by name." It's a usage I haven't seen before, but I guess this is the definitive answer.
$endgroup$
– Maxpm
yesterday
1
$begingroup$
"So R2 is Part No 1006750-25, which is a 510Ω resistor" why is it this value specifically?
$endgroup$
– alex.forencich
20 hours ago
1
$begingroup$
Odds are that bin 25 has that resistor
$endgroup$
– StainlessSteelRat
15 hours ago
1
$begingroup$
@Maxpm It's actually the fully correct use of the word "nominal", it's just that more modern usage (at least in some industries) has skewed towards a corruption which means something closer to "normal/expected" (though the corruption itself certainly already existed at the time).
$endgroup$
– Lightness Races in Orbit
6 hours ago
add a comment |
4
$begingroup$
I suppose they used "nominal" to mean "you should look up this component by name." It's a usage I haven't seen before, but I guess this is the definitive answer.
$endgroup$
– Maxpm
yesterday
1
$begingroup$
"So R2 is Part No 1006750-25, which is a 510Ω resistor" why is it this value specifically?
$endgroup$
– alex.forencich
20 hours ago
1
$begingroup$
Odds are that bin 25 has that resistor
$endgroup$
– StainlessSteelRat
15 hours ago
1
$begingroup$
@Maxpm It's actually the fully correct use of the word "nominal", it's just that more modern usage (at least in some industries) has skewed towards a corruption which means something closer to "normal/expected" (though the corruption itself certainly already existed at the time).
$endgroup$
– Lightness Races in Orbit
6 hours ago
4
4
$begingroup$
I suppose they used "nominal" to mean "you should look up this component by name." It's a usage I haven't seen before, but I guess this is the definitive answer.
$endgroup$
– Maxpm
yesterday
$begingroup$
I suppose they used "nominal" to mean "you should look up this component by name." It's a usage I haven't seen before, but I guess this is the definitive answer.
$endgroup$
– Maxpm
yesterday
1
1
$begingroup$
"So R2 is Part No 1006750-25, which is a 510Ω resistor" why is it this value specifically?
$endgroup$
– alex.forencich
20 hours ago
$begingroup$
"So R2 is Part No 1006750-25, which is a 510Ω resistor" why is it this value specifically?
$endgroup$
– alex.forencich
20 hours ago
1
1
$begingroup$
Odds are that bin 25 has that resistor
$endgroup$
– StainlessSteelRat
15 hours ago
$begingroup$
Odds are that bin 25 has that resistor
$endgroup$
– StainlessSteelRat
15 hours ago
1
1
$begingroup$
@Maxpm It's actually the fully correct use of the word "nominal", it's just that more modern usage (at least in some industries) has skewed towards a corruption which means something closer to "normal/expected" (though the corruption itself certainly already existed at the time).
$endgroup$
– Lightness Races in Orbit
6 hours ago
$begingroup$
@Maxpm It's actually the fully correct use of the word "nominal", it's just that more modern usage (at least in some industries) has skewed towards a corruption which means something closer to "normal/expected" (though the corruption itself certainly already existed at the time).
$endgroup$
– Lightness Races in Orbit
6 hours ago
add a comment |
$begingroup$
The notes in the bottom left of the schematic tell you to "select R3, R7 and R14 per applicable PS from appropriate chart", so "NOM" indicates to look in the tables.
As of yet, I have no idea what to do exactly with the numbers in the appropriate tables, and neither do I have any idea what "PS" means.
I'm a bit in the mist about the exact etymology of "NOM", but it cold be "nomogram", despite some tables giving the values instead of graphs. Maybe it's "Notice of Modification"?
answered yesterday
zebonautzebonaut
16k14490
$endgroup$
2
$begingroup$
That “interpret schematic in accordance standard prescribed by MIL D-70327” is probably where the answer lies.
$endgroup$
– winny
yesterday
1
$begingroup$
"PS" could be "parts"?
$endgroup$
– jochen
12 hours ago
$begingroup$
as in per applicable parts from appropriate chart.
$endgroup$
– StainlessSteelRat
11 hours ago
$begingroup$
PS usually means Post Script – ie the table of values is an addendum to the schematic. Given the words 'applicable' and 'appropriate', I'd guess that different tables might be applicable for different scenarios, e.g. different revisions, or calibrations?
$endgroup$
– Dan W
11 hours ago
$begingroup$
I would guess that the people drawing the schematic knew about what the right value should be, but expected that it might need to be refined through experimentation. If the original draftsman expected that 1K should work, but it turned out that 1.5K was required, it would be necessary to ensure that all copies of the schematic that showed a 1K value were corrected or destroyed. Having to reprint schematics for such a change would have been much more expensive than saying "look at the latest version of XX table for the latest value".
$endgroup$
– supercat
10 hours ago
add a comment |
$begingroup$
The notes in the bottom left of the schematic tell you to "select R3, R7 and R14 per applicable PS from appropriate chart", so "NOM" indicates to look in the tables.
As of yet, I have no idea what to do exactly with the numbers in the appropriate tables, and neither do I have any idea what "PS" means.
I'm a bit in the mist about the exact etymology of "NOM", but it cold be "nomogram", despite some tables giving the values instead of graphs. Maybe it's "Notice of Modification"?
answered yesterday
zebonautzebonaut
16k14490
$endgroup$
2
$begingroup$
That “interpret schematic in accordance standard prescribed by MIL D-70327” is probably where the answer lies.
$endgroup$
– winny
yesterday
1
$begingroup$
"PS" could be "parts"?
$endgroup$
– jochen
12 hours ago
$begingroup$
as in per applicable parts from appropriate chart.
$endgroup$
– StainlessSteelRat
11 hours ago
$begingroup$
PS usually means Post Script – ie the table of values is an addendum to the schematic. Given the words 'applicable' and 'appropriate', I'd guess that different tables might be applicable for different scenarios, e.g. different revisions, or calibrations?
$endgroup$
– Dan W
11 hours ago
$begingroup$
I would guess that the people drawing the schematic knew about what the right value should be, but expected that it might need to be refined through experimentation. If the original draftsman expected that 1K should work, but it turned out that 1.5K was required, it would be necessary to ensure that all copies of the schematic that showed a 1K value were corrected or destroyed. Having to reprint schematics for such a change would have been much more expensive than saying "look at the latest version of XX table for the latest value".
$endgroup$
– supercat
10 hours ago
add a comment |
$begingroup$
The notes in the bottom left of the schematic tell you to "select R3, R7 and R14 per applicable PS from appropriate chart", so "NOM" indicates to look in the tables.
As of yet, I have no idea what to do exactly with the numbers in the appropriate tables, and neither do I have any idea what "PS" means.
I'm a bit in the mist about the exact etymology of "NOM", but it cold be "nomogram", despite some tables giving the values instead of graphs. Maybe it's "Notice of Modification"?
answered yesterday
zebonautzebonaut
16k14490
$endgroup$
The notes in the bottom left of the schematic tell you to "select R3, R7 and R14 per applicable PS from appropriate chart", so "NOM" indicates to look in the tables.
As of yet, I have no idea what to do exactly with the numbers in the appropriate tables, and neither do I have any idea what "PS" means.
I'm a bit in the mist about the exact etymology of "NOM", but it cold be "nomogram", despite some tables giving the values instead of graphs. Maybe it's "Notice of Modification"?
answered yesterday
zebonautzebonaut
16k14490
edited yesterday
answered yesterday
zebonautzebonaut
16k14490
answered yesterday
zebonautzebonaut
16k14490
answered yesterday
zebonautzebonaut
16k14490
16k14490
2
$begingroup$
That “interpret schematic in accordance standard prescribed by MIL D-70327” is probably where the answer lies.
$endgroup$
– winny
yesterday
1
$begingroup$
"PS" could be "parts"?
$endgroup$
– jochen
12 hours ago
$begingroup$
as in per applicable parts from appropriate chart.
$endgroup$
– StainlessSteelRat
11 hours ago
$begingroup$
PS usually means Post Script – ie the table of values is an addendum to the schematic. Given the words 'applicable' and 'appropriate', I'd guess that different tables might be applicable for different scenarios, e.g. different revisions, or calibrations?
$endgroup$
– Dan W
11 hours ago
$begingroup$
I would guess that the people drawing the schematic knew about what the right value should be, but expected that it might need to be refined through experimentation. If the original draftsman expected that 1K should work, but it turned out that 1.5K was required, it would be necessary to ensure that all copies of the schematic that showed a 1K value were corrected or destroyed. Having to reprint schematics for such a change would have been much more expensive than saying "look at the latest version of XX table for the latest value".
$endgroup$
– supercat
10 hours ago
add a comment |
2
$begingroup$
That “interpret schematic in accordance standard prescribed by MIL D-70327” is probably where the answer lies.
$endgroup$
– winny
yesterday
1
$begingroup$
"PS" could be "parts"?
$endgroup$
– jochen
12 hours ago
$begingroup$
as in per applicable parts from appropriate chart.
$endgroup$
– StainlessSteelRat
11 hours ago
$begingroup$
PS usually means Post Script – ie the table of values is an addendum to the schematic. Given the words 'applicable' and 'appropriate', I'd guess that different tables might be applicable for different scenarios, e.g. different revisions, or calibrations?
$endgroup$
– Dan W
11 hours ago
$begingroup$
I would guess that the people drawing the schematic knew about what the right value should be, but expected that it might need to be refined through experimentation. If the original draftsman expected that 1K should work, but it turned out that 1.5K was required, it would be necessary to ensure that all copies of the schematic that showed a 1K value were corrected or destroyed. Having to reprint schematics for such a change would have been much more expensive than saying "look at the latest version of XX table for the latest value".
$endgroup$
– supercat
10 hours ago
2
2
$begingroup$
That “interpret schematic in accordance standard prescribed by MIL D-70327” is probably where the answer lies.
$endgroup$
– winny
yesterday
$begingroup$
That “interpret schematic in accordance standard prescribed by MIL D-70327” is probably where the answer lies.
$endgroup$
– winny
yesterday
1
1
$begingroup$
"PS" could be "parts"?
$endgroup$
– jochen
12 hours ago
$begingroup$
"PS" could be "parts"?
$endgroup$
– jochen
12 hours ago
$begingroup$
as in per applicable parts from appropriate chart.
$endgroup$
– StainlessSteelRat
11 hours ago
$begingroup$
as in per applicable parts from appropriate chart.
$endgroup$
– StainlessSteelRat
11 hours ago
$begingroup$
PS usually means Post Script – ie the table of values is an addendum to the schematic. Given the words 'applicable' and 'appropriate', I'd guess that different tables might be applicable for different scenarios, e.g. different revisions, or calibrations?
$endgroup$
– Dan W
11 hours ago
$begingroup$
PS usually means Post Script – ie the table of values is an addendum to the schematic. Given the words 'applicable' and 'appropriate', I'd guess that different tables might be applicable for different scenarios, e.g. different revisions, or calibrations?
$endgroup$
– Dan W
11 hours ago
$begingroup$
I would guess that the people drawing the schematic knew about what the right value should be, but expected that it might need to be refined through experimentation. If the original draftsman expected that 1K should work, but it turned out that 1.5K was required, it would be necessary to ensure that all copies of the schematic that showed a 1K value were corrected or destroyed. Having to reprint schematics for such a change would have been much more expensive than saying "look at the latest version of XX table for the latest value".
$endgroup$
– supercat
10 hours ago
$begingroup$
I would guess that the people drawing the schematic knew about what the right value should be, but expected that it might need to be refined through experimentation. If the original draftsman expected that 1K should work, but it turned out that 1.5K was required, it would be necessary to ensure that all copies of the schematic that showed a 1K value were corrected or destroyed. Having to reprint schematics for such a change would have been much more expensive than saying "look at the latest version of XX table for the latest value".
$endgroup$
– supercat
10 hours ago
add a comment |
$begingroup$
Nominal is basically used to mean "roughly" or "as stated", or "trade description". But there's a second related meaning which is something like "some small or user-decided (but unspecified) amount/type", and is probably what's meant here. And based on that, is a third meaning, of "some acceptable value", specifically used in space technology.
Meaning "roughly" or "as stated":
You'll see the same word used for many components which aren't sized precisely. For example if you bought some wood or steel for commercial purposes its length might be described as "3m nominal", meaning its about 3m and will do the job, but could be 3m, or 3.02m or something.
- "item of nominal size, nailed at nominal distances _(diagram last page)"
- "PIR (infra red) detector with nominal range (1st para)"
- Aluminium alloys described in terms of nominal compositions
Description of "nominal dimension", on Science Direct: "Parts and components are given nominal dimensions but are allowed to vary within a band of tolerances. Similarly, machine speeds are usually nominal speeds but are frequently allowed to vary slightly within an assigned band of tolerance and so forth."
- Wikipedia entry
- (Note also, in some cases nominal is used to mean a specific type or standard, such as nominal pipe size. But that is clearly not what's meant here.)
Meaning "some small or user-decided (but unspecified) amount/type"
This is a less common usage of the term, as in "leave a nominal air gap" for ventilation. Sorry for poor quality links, I've seen this used in manufacturer documents but can't find examples right now.
- pistonheads forum, "nominal air gap" (2nd post)
- pistonheads forum, "nominal wall design" (9th post)
Dictionary definitions related specifically to space technology:
"Informal (chiefly in the context of space travel): functioning normally or acceptably."
Its not quite the same usage, but perhaps as its in the same field, this was a usage adopted in NASA design, beyond being used to describe the status of a system in operation?
answered 21 hours ago
StilezStilez
1286
$endgroup$
1
$begingroup$
I can't see this being very helpful in context of this question, especially with the StainlessSteelRat's answer showing it has little to do with "roughness". Although one could appreciate getting a wider picture of what it could mean elsewhere.
$endgroup$
– Richard the Spacecat
21 hours ago
$begingroup$
Hopefully expanded and fixed now
$endgroup$
– Stilez
21 hours ago
$begingroup$
I believe it does have some bearing because the design is evolving.
$endgroup$
– StainlessSteelRat
14 hours ago
add a comment |
$begingroup$
Nominal is basically used to mean "roughly" or "as stated", or "trade description". But there's a second related meaning which is something like "some small or user-decided (but unspecified) amount/type", and is probably what's meant here. And based on that, is a third meaning, of "some acceptable value", specifically used in space technology.
Meaning "roughly" or "as stated":
You'll see the same word used for many components which aren't sized precisely. For example if you bought some wood or steel for commercial purposes its length might be described as "3m nominal", meaning its about 3m and will do the job, but could be 3m, or 3.02m or something.
- "item of nominal size, nailed at nominal distances _(diagram last page)"
- "PIR (infra red) detector with nominal range (1st para)"
- Aluminium alloys described in terms of nominal compositions
Description of "nominal dimension", on Science Direct: "Parts and components are given nominal dimensions but are allowed to vary within a band of tolerances. Similarly, machine speeds are usually nominal speeds but are frequently allowed to vary slightly within an assigned band of tolerance and so forth."
- Wikipedia entry
- (Note also, in some cases nominal is used to mean a specific type or standard, such as nominal pipe size. But that is clearly not what's meant here.)
Meaning "some small or user-decided (but unspecified) amount/type"
This is a less common usage of the term, as in "leave a nominal air gap" for ventilation. Sorry for poor quality links, I've seen this used in manufacturer documents but can't find examples right now.
- pistonheads forum, "nominal air gap" (2nd post)
- pistonheads forum, "nominal wall design" (9th post)
Dictionary definitions related specifically to space technology:
"Informal (chiefly in the context of space travel): functioning normally or acceptably."
Its not quite the same usage, but perhaps as its in the same field, this was a usage adopted in NASA design, beyond being used to describe the status of a system in operation?
answered 21 hours ago
StilezStilez
1286
$endgroup$
1
$begingroup$
I can't see this being very helpful in context of this question, especially with the StainlessSteelRat's answer showing it has little to do with "roughness". Although one could appreciate getting a wider picture of what it could mean elsewhere.
$endgroup$
– Richard the Spacecat
21 hours ago
$begingroup$
Hopefully expanded and fixed now
$endgroup$
– Stilez
21 hours ago
$begingroup$
I believe it does have some bearing because the design is evolving.
$endgroup$
– StainlessSteelRat
14 hours ago
add a comment |
$begingroup$
Nominal is basically used to mean "roughly" or "as stated", or "trade description". But there's a second related meaning which is something like "some small or user-decided (but unspecified) amount/type", and is probably what's meant here. And based on that, is a third meaning, of "some acceptable value", specifically used in space technology.
Meaning "roughly" or "as stated":
You'll see the same word used for many components which aren't sized precisely. For example if you bought some wood or steel for commercial purposes its length might be described as "3m nominal", meaning its about 3m and will do the job, but could be 3m, or 3.02m or something.
- "item of nominal size, nailed at nominal distances _(diagram last page)"
- "PIR (infra red) detector with nominal range (1st para)"
- Aluminium alloys described in terms of nominal compositions
Description of "nominal dimension", on Science Direct: "Parts and components are given nominal dimensions but are allowed to vary within a band of tolerances. Similarly, machine speeds are usually nominal speeds but are frequently allowed to vary slightly within an assigned band of tolerance and so forth."
- Wikipedia entry
- (Note also, in some cases nominal is used to mean a specific type or standard, such as nominal pipe size. But that is clearly not what's meant here.)
Meaning "some small or user-decided (but unspecified) amount/type"
This is a less common usage of the term, as in "leave a nominal air gap" for ventilation. Sorry for poor quality links, I've seen this used in manufacturer documents but can't find examples right now.
- pistonheads forum, "nominal air gap" (2nd post)
- pistonheads forum, "nominal wall design" (9th post)
Dictionary definitions related specifically to space technology:
"Informal (chiefly in the context of space travel): functioning normally or acceptably."
Its not quite the same usage, but perhaps as its in the same field, this was a usage adopted in NASA design, beyond being used to describe the status of a system in operation?
answered 21 hours ago
StilezStilez
1286
$endgroup$
Nominal is basically used to mean "roughly" or "as stated", or "trade description". But there's a second related meaning which is something like "some small or user-decided (but unspecified) amount/type", and is probably what's meant here. And based on that, is a third meaning, of "some acceptable value", specifically used in space technology.
Meaning "roughly" or "as stated":
You'll see the same word used for many components which aren't sized precisely. For example if you bought some wood or steel for commercial purposes its length might be described as "3m nominal", meaning its about 3m and will do the job, but could be 3m, or 3.02m or something.
- "item of nominal size, nailed at nominal distances _(diagram last page)"
- "PIR (infra red) detector with nominal range (1st para)"
- Aluminium alloys described in terms of nominal compositions
Description of "nominal dimension", on Science Direct: "Parts and components are given nominal dimensions but are allowed to vary within a band of tolerances. Similarly, machine speeds are usually nominal speeds but are frequently allowed to vary slightly within an assigned band of tolerance and so forth."
- Wikipedia entry
- (Note also, in some cases nominal is used to mean a specific type or standard, such as nominal pipe size. But that is clearly not what's meant here.)
Meaning "some small or user-decided (but unspecified) amount/type"
This is a less common usage of the term, as in "leave a nominal air gap" for ventilation. Sorry for poor quality links, I've seen this used in manufacturer documents but can't find examples right now.
- pistonheads forum, "nominal air gap" (2nd post)
- pistonheads forum, "nominal wall design" (9th post)
Dictionary definitions related specifically to space technology:
"Informal (chiefly in the context of space travel): functioning normally or acceptably."
Its not quite the same usage, but perhaps as its in the same field, this was a usage adopted in NASA design, beyond being used to describe the status of a system in operation?
answered 21 hours ago
StilezStilez
1286
edited 19 hours ago
answered 21 hours ago
StilezStilez
1286
answered 21 hours ago
StilezStilez
1286
answered 21 hours ago
StilezStilez
1286
1286
1
$begingroup$
I can't see this being very helpful in context of this question, especially with the StainlessSteelRat's answer showing it has little to do with "roughness". Although one could appreciate getting a wider picture of what it could mean elsewhere.
$endgroup$
– Richard the Spacecat
21 hours ago
$begingroup$
Hopefully expanded and fixed now
$endgroup$
– Stilez
21 hours ago
$begingroup$
I believe it does have some bearing because the design is evolving.
$endgroup$
– StainlessSteelRat
14 hours ago
add a comment |
1
$begingroup$
I can't see this being very helpful in context of this question, especially with the StainlessSteelRat's answer showing it has little to do with "roughness". Although one could appreciate getting a wider picture of what it could mean elsewhere.
$endgroup$
– Richard the Spacecat
21 hours ago
$begingroup$
Hopefully expanded and fixed now
$endgroup$
– Stilez
21 hours ago
$begingroup$
I believe it does have some bearing because the design is evolving.
$endgroup$
– StainlessSteelRat
14 hours ago
1
1
$begingroup$
I can't see this being very helpful in context of this question, especially with the StainlessSteelRat's answer showing it has little to do with "roughness". Although one could appreciate getting a wider picture of what it could mean elsewhere.
$endgroup$
– Richard the Spacecat
21 hours ago
$begingroup$
I can't see this being very helpful in context of this question, especially with the StainlessSteelRat's answer showing it has little to do with "roughness". Although one could appreciate getting a wider picture of what it could mean elsewhere.
$endgroup$
– Richard the Spacecat
21 hours ago
$begingroup$
Hopefully expanded and fixed now
$endgroup$
– Stilez
21 hours ago
$begingroup$
Hopefully expanded and fixed now
$endgroup$
– Stilez
21 hours ago
$begingroup$
I believe it does have some bearing because the design is evolving.
$endgroup$
– StainlessSteelRat
14 hours ago
$begingroup$
I believe it does have some bearing because the design is evolving.
$endgroup$
– StainlessSteelRat
14 hours ago
add a comment |
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28
$begingroup$
It means the schematic software is very hungry and has started eating your circuit. I see further down it has started naming other components after Family Guy characters, so it must be going mad with hunger.
$endgroup$
– Benjamin Wharton
yesterday
1
$begingroup$
Now or NOM @BenjaminWharton that would have to be NOM NOM NOM.
$endgroup$
– StainlessSteelRat
yesterday
3
$begingroup$
It's old enough the schematic software might be called Dave or Fran
$endgroup$
– Journeyman Geek
yesterday
3
$begingroup$
@StainlessSteelRat Shouldn't that be Ohm Nom Nom?
$endgroup$
– fluffy
yesterday
2
$begingroup$
Intentional use of Fran actually. There's always been women in tech who're forgotten. It's entirely plausible the schematics or parts of them were done by women.
$endgroup$
– Journeyman Geek
19 hours ago