At 02:33 PM 2/13/01 -0800, Dennis Saputelli wrote:
>I hope it doesn't give CR for a diode !
standard is D or CR. I prefer D because it takes up less room. Sometimes VR
is also used for a diode used as a voltage regulator
>or IC for a U
right. U is "inseparable subassembly, integrated-circuit package,
microcircuit, micromodule," though A is used for separable subassemblies.
IC is completely nonstandard and unnecessarily long.
(longer names, especially for common parts, make problems on the schematic
and on the component legend [Protel "overlay."])
>so what do you do with a 3 pin regulator that looks like a Q?
>I have taken to naming them Q or sometimes REG
>if you name them U the assembly people look all around for an IC type
>package
Any assembler who hasn't seen a 78L05 or the like called U-something has
been asleep for the last twenty years or more. I'd say that one out of
fifty schematics I receive deviates from that.
Components are named for their function and character, not for their
package style. If I have an inductor that looks like a resistor, do I call
it "R"? I think not.
>personally I like Z for a zener and TZ for a tranzorb, but I'm sure
>these are non standard and will cause disagreement
>this way you can look at a board and have a small idea what is going on
True. However, standards in general help that process and leaving them can
hinder it. Z for zener is fairly harmless, though it is usually pretty
obvious what is a reverse-bias diode and what is not.
By this argument, using Q for a regulator will *really* confuse the tech.
>the real fun comes in trying to get J $ P to be logical and consistent
It's much easier than one might think, though most engineers don't know the
standard.
The primary distinguishing characteristic is that J is stationary and P is
mobile. If both J and P are mobile, or are equivalent stationary, which
usually means cables floating around to be connected together, then P is
male and J is female.
That's the standard. I'd add that if male and female are not
distinguishable, as with some connectors which have both pins (male) and
sockets (female), then I would make the hot connector (powered when
unconnected) J and the other P, if there is any difference, which is what
one would do anyway with good connector design.
I.e., the wall socket is J and the lamp plug is P, because:
(1) The wall socket is stationary.
(2) The wall socket is female.
(3) The wall socket is powered.
So an extension cord has a P on the end which goes into the wall, and a J
on the other end, even though both ends are stationary. Except for the one
I made in an emergency when I had a job to finish and the power company
told me my block's power was going off for the day and I rented a generator
but not a transfer switch. That cord had P on both ends. Now I worry about
it sitting around, that someone might need an extension cord and plug it
in, before noticing that the other end was a bit unusual.
[EMAIL PROTECTED]
Abdulrahman Lomax
P.O. Box 690
El Verano, CA 95433
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