Understand the difference.

Compare the meaning, drawing context and source references of two entries. A similar graphic or shared abbreviation does not establish equivalence.

VDR

Symbols

Varistor

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.

Drawing use

SLD / Schematic

Application

Control circuits

Reference family

IEC / Manufacturer

A distinction that matters

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

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R

Symbols

Resistor

A resistor representation identifies a resistive component in a circuit. Different drawing conventions can use different basic outlines, while additional qualifiers distinguish variable resistors, shunts or heating elements. The value, rating and purpose are separate annotations.

Drawing use

Schematic

Application

Control circuits

Reference family

IEC / IEEE / ANSI

A distinction that matters

IEC-style rectangular and other conventional resistor depictions can describe the same component concept, but qualifiers and documentation still matter.

Full referenceAdd to legend

Original educational previews. Follow the source references on each full entry for the appropriate standard or selected product.