Challenge of the Day: from halogen transformer to battery charger

te:

s, D, Tr, Q, BR etc

t ones in my truck alternator. The bridge I just notate as D. It's drawn on the schematic as a diode bridge, so why add a special ref des especially a two letter one? I don't think I've ever used a two letter ref des.

s (much as D is adequate for diode bridges) and J is the typical designator for connectors. Why buck convention?

Ok, to each his own.

I don't recall ever seeing CN on a schematic. I have seen J and P used for jack and plug, but as others have indicated, the terms jack and plug are n ot so clear with some connector types. In many cases I've seen J used on a ll connectors, so I now just use J.

I also don't recall ever seeing IC used for devices.

One place where I have seen variations is both X and Y used for crystals. I can't recall any other variations in the standard designators, but there may have been some. As others have mentioned, it is not uncommon for board s to be crowded so that two letter ref des would need space that might not be available. I know the stuff I design is often *very* crowded. In one c ase I had to put the ref des over top of vias and had to deal with the PWB fabricators wanting to clip excessively around them. We discussed the conc erns and I got them to only clip close to the hole and not around the entir e pad making the ref des legible again.

Rick C.

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gnuarm.deletethisbit
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te:

s, D, Tr, Q, BR etc

t ones in my truck alternator. The bridge I just notate as D. It's drawn on the schematic as a diode bridge, so why add a special ref des especially a two letter one? I don't think I've ever used a two letter ref des.

s (much as D is adequate for diode bridges) and J is the typical designator for connectors. Why buck convention?

Oh yeah, I use R for jumper because that's what they are, zero ohm resistor s.

Rick C.

Reply to
gnuarm.deletethisbit

I use 'R' for allegedly-zero-ohm resistors. "JP" for jumper pins is about the only two-letter ref des I've ever used, iirc, and that's about one board in ten. Connectors are generally pretty big, so the silkscreen space required by 'CN' is a nit, but 'RA' and 'IC' are a bit more of an issue. It's a matter of taste.

Cheers

Phil Hobbs

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Dr Philip C D Hobbs 
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Phil Hobbs

Maybe this will help:

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John S

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