Thermistor symbol
Also called NTC, PTC, Temperature dependent resistor
A resistor whose resistance changes with temperature: down as it warms for an NTC, up for a PTC. The bent line through it means the change is set by a physical quantity, not adjusted by hand.
ANSI / IEEE
IEC 60617What the thermistor symbol means
A resistor whose resistance changes with temperature: down as it warms for an NTC, up for a PTC. The bent line through it means the change is set by a physical quantity, not adjusted by hand.
ANSI and IEC symbols
Where you see it
Temperature sensing, inrush current limiting and motor winding protection.
What is written next to it
On a schematic, the thermistor usually carries its designator, type and resistance at 25 °C, such as RT1 NTC 10 kΩ.
Related symbols
Frequently asked questions
What does the thermistor symbol look like?
On ANSI drawings: A zigzag with a bent line through it, marked t°. In IEC 60617: A rectangle with a bent line through it, marked t° (or θ).
Is the thermistor symbol the same in IEC and ANSI?
No. A rectangle with a bent line through it, marked t° (or θ).
Where is a thermistor used?
Temperature sensing, inrush current limiting and motor winding protection.
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