Standard nomenclature for component types

There are actually standards to address this, IEC 60617 (also known as British Standard BS 3939), ANSI standard Y32 (also known as IEEE Std 315), Australian Standard AS 1102

Below is a table of some common markings from this link to an old revision of a Wikipedia article

  • Designator Component Type
  • 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


Component name abbreviations widely used in industry:

  • 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 transistor(display)
  • 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

I've used the canonical R, C, D, Q, U scheme at both career stops thus far.

My first stop would differentiate between 'male' and 'female' connectors by using J for 'jacks' (i.e. female) and P for 'pins' (i.e. male).

I currently use RT for NTC/PTC thermistors and RV for MOVs. Odd that the powers-that-be only opted for such a narrow amount of reference designator innovation.