Designator | Component Type
--- | ---
A | Sub-assembly or plug-in module
BT | Battery
C | Capacitor
D | Diode
DS | Display
F | Fuse
FB | Ferrite bead
FD | Fiducial
FL | Filter
H | Hardware (mounting screws, etc)
J | Jack, fixed part of a connector pair
JP | Jumper / link
K | Relay
L | Inductor, coil, ferrite bead
LS | Loudspeaker or buzzer
M | Motor
MK | Microphone
P | Plug, movable part of a connector pair
Q | Transistor
R | Resistor
RN | Resistor network
RT | Thermistor
RV | Varistor
SW | Switch
T | Transformer
TC | Thermocouple
TP | Test point
U | Integrated circuit (IC)
Y | Crystal / oscillator
Z | Zener diode