Deciphering schematics - Help!!!

Charlie

.. . Mouse . ..
Joined
Jan 20, 2008
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While perusing a set of schematics for ideas (yes, I'm that sad) I came across a recurring (use of) a symbol I couldn't make head of tail of:

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The symbol I'm referring to is the circle with a diagonal cross through it. I initially presumed the designer of said schematic liked to put a bunch of lamps on their boards for some reason given that was my understanding of the meaning of said symbol. That doesn't make sense in the above context so how am I to interpret this..?
Left to right:
-R9 is a three pin network resistor pulling lines 10 and 9 up to 5v?
-R13 is a nine pin network resistor pulling eight lines up to 5v?
...and so on...
...the final image just being a standard resistor, or part of a larger R9 network also pulled up to 5v..?

My assumption being the symbol I thought of as a 'lamp' is used here to denote a connection... How close / far am I from making sense of this?

Many thanks.

PS
In case any are wondering it's a schematic for an Apple II Z80 board whose workings I'm trying to figure out - yep, that sad!
 
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They are star resistor networks with the common connected to the 5V rail. Each "lamp" is where the other end of the resistor is connected.

Bryce.
 
yep,pullup resistors

EDIT:,yeah it is a odd way of doing it,it is a resistor network,but the package is individual resistors in the package.maybe they thought it would be harder to draw the part in,i dont know
 
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It just depends on what library the person was using. It looks like it's done in Eagle and there are some very unusual non-standard "homemade" symbols flying about for that. Resistor networks are always a difficult symbol for schematics, because they usually connect to multiple lines around the board.

Bryce.
 
I wasn't too far off, good. Thanks very much, I appreciate your advice.
 
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Yes, it's a very generic symbol, I've seen it used for Test points, vias, mounting holes, bulbs and fiducials (you'll have to look that one up if you're not involved in PCB manufacturing :D ).

Bryce.
 
Yes, it's a very generic symbol, I've seen it used for Test points, vias, mounting holes, bulbs and fiducials (you'll have to look that one up if you're not involved in PCB manufacturing :D ).
I didn't know the word 'fiducials' but it turns out that I've used them myself in the past when I wanted to etch my own 2-layer PCBs and I needed some fix points to align the two layers. :)
 
It's used commonly in the electronics industry, but I'd be suprised if many electronics hobbiests know or use the word.

Now you have a word for those markings, next time you use them :)

Bryce.
 
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Ah, a new word as well a new understanding. Thanks again.
 
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