varistor
LowTechnical
Definition
Meaning
An electronic component whose electrical resistance changes with the applied voltage.
A voltage-dependent, nonlinear resistor used for surge protection and transient suppression in electronic circuits. Its resistance decreases sharply when the voltage exceeds a certain threshold.
Linguistics
Semantic Notes
A portmanteau of 'variable' and 'resistor'. It refers specifically to a voltage-sensitive device, not a general variable resistor like a rheostat or potentiometer.
Dialectal Variation
British vs American Usage
Differences
No significant lexical differences; the term is standard in global electronics and engineering.
Connotations
None beyond its technical definition.
Frequency
Used with equal, low frequency in both UK and US technical contexts.
Vocabulary
Collocations
Grammar
Valency Patterns
The varistor protects [the circuit] from [voltage spikes]A varistor is connected [across/in parallel with] [a component]Vocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “None”
Usage
Context Usage
Business
Used in procurement, specifications, and technical documentation for electronic components.
Academic
Found in electrical engineering, physics, and electronics textbooks and research papers on circuit protection.
Everyday
Almost never used outside of electronics hobbyist or repair contexts.
Technical
The primary context. Used in datasheets, circuit diagrams, schematics, and engineering discussions on surge protection.
Examples
By Part of Speech
adjective
British English
- The varistor protection was inadequate for the industrial environment.
American English
- The varistor-based suppressor module is UL-listed.
Examples
By CEFR Level
- This little part is called a varistor.
- For basic surge protection, you can add a varistor across the power supply inputs.
- The metal oxide varistor's clamping characteristics degraded after multiple transient events, necessitating its replacement in the protective circuit.
Learning
Memory Aids
Mnemonic
Think: VARiable resISTOR -> VARISTOR. It's a resistor that varies its resistance based on voltage.
Conceptual Metaphor
A 'pressure-sensitive valve' for electricity; it 'opens' (conducts) when electrical 'pressure' (voltage) gets too high, diverting the excess.
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Do not confuse with 'резистор' (resistor). A varistor is a 'варистор' in Russian.
- Avoid translating it as a generic 'переменный резистор' (variable resistor), which is a different component (potentiometer).
Common Mistakes
- Pronouncing it as 'var-EE-stor' (correct is 'va-RIS-tor').
- Confusing it with a thermistor (temperature-sensitive resistor).
- Using it to refer to a manually adjustable resistor.
Practice
Quiz
What is the primary function of a varistor?
FAQ
Frequently Asked Questions
No. A fuse breaks the circuit permanently when current is too high. A varistor temporarily conducts excess voltage to ground, then returns to a high-resistance state.
They are both used for voltage clamping, but a varistor is bidirectional (works on AC/DC) and is less precise, making it better for surge suppression than precise voltage regulation.
Inside power strips, AC adapters, telephone line protectors, and on the power input stages of almost all electronic devices to protect against voltage spikes.
A failed varistor may show visible cracks, burn marks, or measure as a short circuit (very low resistance). It often fails during a severe surge.