Common Reference Designators
| AT | Attenuator |
| BR | Bridge rectifier |
| BT | Battery |
| C | Capacitor |
| CN | Capacitor network |
| D | Diode (including zeners, thyristors and LEDs) |
| DL | Delay line |
| DS | Display |
| F | Fuse |
| FB | or FEB Ferrite bead |
| FD | Fiducial |
| J | Jack connector (female) |
| JP | Link (Jumper) |
| K | Relay |
| L | Inductor |
| LS | Loudspeaker or buzzer |
| M | Motor |
| MK | Microphone |
| MP | Mechanical part (including screws and fasteners) |
| P | Plug connector (male) |
| PS | Power supply |
| Q | Transistor (all types) |
| R | Resistor |
| RN | Resistor network |
| RT | Thermistor |
| RV | Varistor |
| S | Switch (all types, including push-buttons) |
| T | Transformer |
| TC | Thermocouple |
| TUN | Tuner |
| TP | Test point |
| U | Integrated circuit |
| V | Vacuum Tube |
| VR | Variable Resistor (potentiometer or rheostat) |
| X | Transducer not matching any other category |
| Y | Crystal or oscillator |
| Z | Zener Diode |
| AE | aerial, antenna |
| B | battery |
| BR | bridge rectifier |
| C | capacitor |
| CRT | cathode ray tube |
| D or CR | diode |
| DSP | digital signal processor |
| F | fuse |
| FET | field effect transistor |
| GDT | gas discharge tube |
| IC | integrated circuit |
| J | wire link (“jumper”) |
| JFET | junction gate field-effect transistor |
| L | inductor |
| LCD | Liquid crystal display |
| LDR | light dependent resistor |
| LED | light emitting diode |
| LS | speaker |
| M | motor |
| MCB | circuit breaker |
| Mic | microphone |
| MOSFET | Metal oxide semiconductor field effect transistor |
| Ne | neon lamp |
| OP | Operational Amplifier |
| PCB | Printed circuit board |
| PU | pickup |
| Q | transistor |
| R | resistor |
| RLA/RY | relay |
| SCR | silicon controlled rectifier |
| SW | switch |
| T | transformer |
| TFT | thin film transistordisplay |
| TH | thermistor |
| TP | test point |
| Tr | transistor |
| U | integrated circuit |
| V | valve (tube) |
| VC | variable capacitor |
| VFD | vacuum fluorescent display |
| VLSI | very large scale integration |
| VR | variable resistor |
| X | crystal, ceramic resonator |
| XMER | transformer |
| XTAL | crystal |
| Z or ZD | Zener diode |