Resistor symbols

 

All types of resistors have their own resistor symbols which are used when a circuit diagram is drawn. This page will explain the different standards which are used for resistor symbols and display the most common symbols.

Standards for resistor symbols

Several standards exist, which describe how the different components should be displayed. In the past a lot of countries or even industries used their own standards, which can be confusing. Nowadays the IEC 60617 standard is international standard for these electronic symbols. However the local standards are still used from time to time. In general, the ANSI standard is still common in the United States. Some examples of standards which describe resistor symbols:

  • IEC 60617 (International)
  • ANSI Y32 / IEEE 315 (US) – old
  • DIN 40900 (Germany) – old
  • AS 1102 (Australia) – old

Sometimes the symbol for a particular device is different when it is used in another field of application. Other symbols are used in electronics then for example in architecture and buildings. On top of this, many local deviations from the international standards exist. The following table shows the most common resistor symbols for electronics design.

Schematic symbols 

TypeAbbreviationIEC (International)ANSI (US)
Fixed resistorRresistor symbolresistor symbol - US
Heating resistorheater resistor symbol
Variable resistorsVR
PotentiometerPotentiometer symbol

Potentiometer symbol US

Trimming potentiometerTrimpot symbolTrimpot symbol US
RheostatRheostat symbolRheostat symbol US
Preset resistor

Preset resistor symbol

preset symbol US
Dependent resistors
Photo resistor or
Light dependent resistor
LDR LDR symbol LDR symbol US
Varistor or 
Voltage dependent resistor 
VDR
RV
MOV 
VDR symbolVDR symbol US
NTC thermistorNTC
RT
thermistor symbolthermistor symbol american
PTC thermistorPTC
RT
PTC thermistor symbolPTC thermistor symbol US
Magneto resistor or
Magnetic dependent resistor 
 MDRmagneto resistor symbolmagneto resistor symbol US