I found this symbol in a vendor circuit diagram. What does it mean? It looks like they are trying to convey some sort of limiting.

It's a resistor symbol with a line over the top that has both the top and bottom ends flattened.

unusual resistor symbol

  • 3
    \$\begingroup\$ It appears to be a varistor (voltage-dependent resistor). Not sure if a duplicate, so I'm posting this as a comment. \$\endgroup\$ – nanofarad Jul 17 '15 at 17:35
  • \$\begingroup\$ It is indeed the IEEE symbol for a Varistor. The IEC symbol is a square box with the same line through it. Source: electronicshub.org/varistor \$\endgroup\$ – Tom Carpenter Jul 17 '15 at 17:38
  • 1
    \$\begingroup\$ @AbhishekTyagi No, a variable resistor has a different symbol - it is a diagonal line with an arrow on the end, not what is shown in the drawing above. The symbol shown is a varistor as 3 of us have pointed out (see the link I posted). \$\endgroup\$ – Tom Carpenter Jul 17 '15 at 18:09
  • \$\begingroup\$ @TomCarpenter Thanks a lot for pointing this out...its a big mistake i did here....having cold ...;) \$\endgroup\$ – Abhishek Tyagi Jul 17 '15 at 18:28
  • \$\begingroup\$ V.D.R. (Voltage dependent resistor) \$\endgroup\$ – Always Confused Jul 1 '16 at 18:55

Doing a google search of "Resistor Symbol" and then looking at images, I came across this.


enter image description here

According to the site, its a varistor tolerated symbol.

a: resistor , general symbol

b: resistor , tolerated symbol

c: resistor , un-standard symbol

d: resistor with variable resistance

e: resistor with mobile contact

f: resistor with mobile contact and stop position

g: potentiometer with mobile contact

h: potentiometer with mobile contact, general symbol

i: potentiometer with preset adjustment

j: two plugs resistor

k: shunt resistor

l: thermal resistor

m: thermistor general symbol

n: thermistor tolerated symbol

o: varistor general symbol

p: varistor tolerated symbol

  • \$\begingroup\$ I'd seen c) used for memristors (perhaps erroneously.) \$\endgroup\$ – rdtsc Jul 17 '15 at 22:07
  • \$\begingroup\$ I have seen c) used for resistive heaters. \$\endgroup\$ – Nick Alexeev Jul 18 '15 at 5:27

It is better to use oficial symbols and not whatever gather from web.

Official Varistor symbol according to the IEEE "Graphic Symbols for Electrical and Electronics Diagrams" (IEEE std 315-1975) is the follow:

enter image description here Please refere to the follow standards if you want to communicate and distribute your diagram

enter image description here


It is a varistor , a voltage dependent resistor


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