Are there any standards?
My standard is not to exceed 3 positions in the name becasue it will be too long to get visible on the pcb.
My standard is:
Left channel
R
C
T
Right channel
R = E (resistors)
C = G (caps)
T = V (transistors)
R34 in the left channel is E34 in the right etc.
I use different letters which not are used for anything standard.
My goal is to have the designators visible when the part is mounted
My standard is not to exceed 3 positions in the name becasue it will be too long to get visible on the pcb.
My standard is:
Left channel
R
C
T
Right channel
R = E (resistors)
C = G (caps)
T = V (transistors)
R34 in the left channel is E34 in the right etc.
I use different letters which not are used for anything standard.
My goal is to have the designators visible when the part is mounted
AuroraB said:
It differs a bit in which continent you are. In the US, they often use Q for transistors, while in Europe we often see T. U is often used for an integrated circuit, but you also see Q used here. J I think is most often used for connectors, although you also see it for FETs (presumably from "Junction FET"). R, C and D are so standard that I can't remember seeing other uses, although very rare you see CR for diodes specifically in older Japanese and US diagrams (presumably from the old "crystal" days).
For multiple channel systems you often see that they add 100 to all designations, like R122 in one channel would be R222 in another and R322 in yet another channel. P-A's "standard" to use E for resistors in another channel is a sure recipe for confusion (except for him maybe, but then again he DOES publish on this forum).
Jan Didden
Since schematic, partslist and layout is 100% connected to each other there is no way to mixup especially when I also have explained this and it is assumed that people should read instructions and so far noone has had any problems with that.janneman said:
There is actually a standard but the one I know is old and is related to electromechanical designs.
The problem with this standard is that it's very confusing.
D = digital IC
H = analog IC
V or was it Q = transistors, or semiconductors
etc, etc.
One customer at work demanded this pretty weird standard.
My idea was to use letters which aren't used to anything so you must get info what E, G etc stands for.
P-A,
I don't want to split more hairs than necessary
but the thing is that E stands for a voltage controlled current source and G for a transconductance source. Granted that you won't see too much of those on pcb's but in the sim world they are the standard notation for that.
Furthermore E is sometimes used to indicate ohms like K is used to indicate kilo ohms. For instance, on many Philips schematics they used 50E for 50 ohms; you propose E50 for "R"50.
My point is that there are perfectly acceptable and accepted ways to do this. Inventing yet another way, even if you document it (which I think is extra work you're not looking for) has NO advantage but several disadvantages. But hey, if it makes you happy.
Jan Didden
I don't want to split more hairs than necessary
but the thing is that E stands for a voltage controlled current source and G for a transconductance source. Granted that you won't see too much of those on pcb's but in the sim world they are the standard notation for that.Furthermore E is sometimes used to indicate ohms like K is used to indicate kilo ohms. For instance, on many Philips schematics they used 50E for 50 ohms; you propose E50 for "R"50.
My point is that there are perfectly acceptable and accepted ways to do this. Inventing yet another way, even if you document it (which I think is extra work you're not looking for) has NO advantage but several disadvantages. But hey, if it makes you happy.
Jan Didden
Why don't you use Chinese characters (ideograms), then?
, jonathan carr
you can use the SPICE symbols for components -- understood around the globe -- the term "U" is both integrated circuit and "user-defined component" in some schematic capture and sim programs.
the problem with trying to "standardize" numbering is that once things get messy and all tweaked-up there is the temptation to use the "renumbering tool" -- which will work left to right, top to bottom unless otherwise directed. whenever you "renumber" you also have to remember to "forward annotate" your design in the PCB design program.
some schematic capture programs allow you to dump the "bill of materials" into Excel -- a good way of telling if you have been inconsistent in numbering.
the problem with trying to "standardize" numbering is that once things get messy and all tweaked-up there is the temptation to use the "renumbering tool" -- which will work left to right, top to bottom unless otherwise directed. whenever you "renumber" you also have to remember to "forward annotate" your design in the PCB design program.
some schematic capture programs allow you to dump the "bill of materials" into Excel -- a good way of telling if you have been inconsistent in numbering.
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