Hi Jack,

CR stands for current regulator or current rectifier.
I think U stands for unit.
K could be for contact, as C is also taken.
We still use P for plugs.
A or U can be used for subassemblies.

These and all other prefixes (Class Designation Letters) are documented in
IEEE Std 315-1975 (ANSI Y32.2-1975) (CSA Z99-1975)

Regards,
Roy

Roy H. Beckman, C.E.T.
Senior PCB Designer / System Administrator
Harris Canada, Inc.
6732 - 8th Street, N.E.
Calgary, Alberta, Canada T2E 8M4
Phone:  403-295-4758
Fax:  403-295-4622
email:[log in to unmask] <mailto:email:[log in to unmask]>  



> -----Original Message-----
> From: Jack Olson [mailto:[log in to unmask]]
> Sent: Monday, January 10, 2000 11:22 AM
> To: [log in to unmask]
> Subject: [DC] Reference Designators
> 
> 
> Something I overheard this morning got me wondering...
> 
> Have any of you been around long enough to know why a diode 
> would have a
> designator of CR? What does the CR mean?
> 
> What does the U mean on an Integrated Circuit?
> 
> Is the K on relays arbitrary since R is used by resistors?
> 
> Does anyone really use P anymore for plugs?
> (everything I've seen lately is J on connectors, no matter if 
> it is a socket
> or a plug)
> 
> What do you use for submodules or subassemblies?
> 
> Not really important, I was just curious....
> 
> Jack
>