SMD NTC Thermistors and Thin-Film Temperature Sensors
SMD NTC thermistors are surface-mount temperature-dependent resistors: their resistance decreases as temperature rises. This collection is primarily chip thermistors in 0402, 0603, 0805 and 1206 package options, plus thin-film and lid-contact temperature sensors. A few through-hole inrush limiters and other protection devices also appear here. Select a specific variant for its electrical function and mounting style; an “SMD” keyword in a listing does not make every item a PCB chip sensor.
Chip thermistors versus assembled sensors
- PCB chip NTCs: compact two-terminal components for temperature feedback on a circuit board. Listings offer 0402, 0603, 0805 and 1206 sizes with differing resistance-at-25 °C (R25), B values and tolerances; compare the exact selected option and its footprint before ordering.
- Thin-film MF5B-style sensors: flexible or leaded sensing strips offered in different lengths and resistances. They place the sensing area away from a conventional chip footprint and need the right mounting, thermal contact and strain relief.
- Lid- or surface-contact probes: assembled 100 kΩ patch sensors and wired threaded or silicone-lead probes appear in the range. Check the controller's specified curve, cable termination and contact geometry. A rice-cooker or pressure-cooker reference in a title is not proof of compatibility with a particular appliance.
- Mixed protection components: MF72 and SCK-style disc NTCs are commonly described for inrush limiting rather than calibrated temperature measurement; JK60 protection items also appear. These parts cannot be chosen from an SMD sensor's R25/B-curve criteria alone.
Selection checklist for temperature measurement
- Match R25 and the curve: check nominal resistance at 25 °C, resistance tolerance, B-value definition (including its reference-temperature pair) and preferably a full resistance-temperature table. Two 10 kΩ options can produce different readings away from 25 °C if their curves differ.
- Check circuit and footprint: match PCB land pattern, component dimensions, termination and soldering limits for chip parts. The 0402/0603/0805/1206 code indicates physical package, not a common calibration, power rating or interchangeability.
- Check thermal design: confirm operating-temperature range, dissipation factor, thermal time constant and measurement current where documented. Self-heating, nearby PCB hot spots, airflow and contact pressure can shift the measured temperature.
- Match the assembly: for flexible or lid-mounted parts, verify lead length, insulation, connector/pinout, mounting location and the temperature limits of the entire assembly, not just the sensing element.
- Read the chosen pack and option: resistance, B curve, package size, tolerance and piece count vary between listings and within multi-option listings. A brand, “original” claim or reference part number should not substitute for documented specifications or provenance.
Not the same as an inrush limiter
A sensor NTC is measured with a suitable controller input and a matching lookup curve. An NTC inrush limiter starts cold and warms under load to limit startup current; choose it by cold resistance, steady-state current, surge-energy capability, hot-state behavior and cooling/restart conditions. Neither type should be substituted for a PTC protection part, thermal switch, platinum RTD or digital sensor solely because it is called a thermistor. Check the selected product's data before using any part in a safety-related circuit.
Typical uses and ordering information
Correctly matched chip thermistors support PCB temperature monitoring, compensation and control; assembled strips and patch sensors can measure temperatures at a mounting surface or in an appliance. For a BOM or replacement, record the exact variant, R25, tolerance, B definition and temperature curve, package or sensor dimensions, operating range, termination, required mounting and pack quantity. Use equipment service specifications when replacing an appliance sensor.
Frequently asked questions
Does 0805 tell me the resistance or B value?
No. It describes the package size; R25, B curve, tolerance and working limits are separate specifications for the selected part.
Can a thin-film sensor replace a chip NTC?
Only after verifying its curve, mounting, lead and thermal behavior in the target circuit. Similar nominal resistance is insufficient.
Are MF72 discs suitable for precision temperature sensing?
They are sold here as inrush-related components, not assumed calibrated probes. Choose a documented sensing-grade part and compatible readout for temperature measurement.
Will a 100 kΩ lid patch work with every cooker?
No. Confirm the appliance's original sensor curve, mounting and electrical connection using its service documentation.
