# Varistor

Canonical URL: https://eloragrid.ai/symbols/varistor
Publisher: Elora Grid
Updated: 2026-10-13
Lookup label: VDR
Drawing use: SLD, Schematic
Reference families: IEC, Manufacturer

A varistor is a voltage-dependent resistive component used in a documented circuit, often for transient limiting.

## What it represents

A varistor is a voltage-dependent resistive component used in a documented circuit, often for transient limiting. Its rating and protected connection are needed beyond the generic outline.

## How to read it

- Check continuous-voltage rating separately from clamping-related data.
- The preview is an original explanation of this function. Match the actual drawing convention to its legend and the selected equipment documentation.

## Information to show or reference

- Identify protected terminals
- State selected voltage rating
- Reference energy and surge data

## Important distinction

A varistor is nonlinear; a fixed resistor does not provide the same voltage-dependent function.

## Facts

- Drawing role: Passive circuit element
- Representation scope: Functional concept; not an official standard graphic or a product footprint
- Public vendor block reference: HVR1R3, VVR1R3 (Autodesk identifiers; not IEC symbol numbers)
- Identifier status: The short label is a functional lookup label, not an assigned IEC or IEEE symbol number. Any separately listed Autodesk code is a verified vendor block name.

## Public references

- [Resistors and heater-element symbols](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-1D071951-D38E-4B15-8B9E-C30ECBD55C19.htm) — Autodesk. Public documentation of this equipment function or named vendor variant; the illustration is independently authored and is not the source graphic.

## Graphic scope

Independent original educational concept illustration by Elora Grid. Not a certified standards graphic or manufacturer footprint. Unitless; not to scale. Original artwork licence: https://creativecommons.org/licenses/by/4.0/. Publisher material is linked only.