Schematic component naming

Looking at some of my old schematics, I can see that I haven't been entirely consistent when naming components. Nowhere near consistent, actually.

Sometimes I have used "T" as prefix for transistors and sometimes "Q". And especially IC's that are prefixed either with "U" or "IC" – often I have used both in a single schematic. And also connectors that are named "CON" or "J" or "JP". Sloppy…

Well, no more! This page on Wikipedia has a nice table with designators for various component types (even though it does not comply with with IEEE- or ANSI-whatever standard).

So this is what I will use henceforth:

Designator Component type
R Resistors
C Capacitors
L Inductors, coils
D Diodes – all types including Zener, Schottky and LEDs
U IC's of all kinds. Technically it is used for "Inseparable Assemblies".
J Connectors. The more fixed part of a connector pair (often the part soldered to the PCB).
P Plugs. The less fixed part of a connector pair (i.e. the one on the wire).
K Relays
M Motors
Q Transistors – all types including MOSFETs, IGBTs, BJTs etc.
S Switches
Y Crystals and oscillators
X Transducers/sensors (no, X is not for crystals anymore).
FB Ferrite beads
BT Batteries
JP Jumpers. Not connectors but only actual jumpers that are linked or unlinked.
TP Test point (pad or pin for measuring)
MP Mechanical parts (standoffs, screws, mounting hardware etc.)

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