TDK B57321V2103J060 10K ohm 5% 3940K NTC 0603 SMD Thermistor 100 PCS

TDK B57321V2103J060 negative-temperature-coefficient thermistor rated 10K ohm at 25°C with ±5% resistance tolerance in the compact 0603 / 1608 metric surface-mount package. The device has a B25/50 value of 3940 K, B25/85 value of 3980 K, and B25/100 value of 4000 K.

Unlike a fixed resistor, an NTC thermistor decreases in resistance as temperature rises. This characteristic allows the device to act as a compact electronic temperature sensor for monitoring, compensation, protection, regulation, and control circuits.

TDK specifies operation from approximately -55°C to +125°C with maximum power dissipation of approximately 180 mW. The compact 0603 package is suitable for automated PCB assembly and temperature measurement close to heat-generating components.

Original Digi-Key packaging identifies TDK B57321V2103J060, 10K ohm NTC thermistor, 3940 K B-value, 0603 package, and country of origin Croatia.

Lifecycle: ACTIVE.

HISTORICAL BACKGROUND: TDK was founded in Japan in 1935 as Tokyo Denki Kagaku Kogyo and became one of the world’s major manufacturers of magnetic materials, capacitors, inductors, sensors, ferrites, and other electronic components.

Temperature-sensitive resistors have been used for decades in electronic equipment to convert temperature changes into measurable electrical resistance changes. NTC thermistors became particularly important because they provide high temperature sensitivity using a very small and inexpensive component.

In an NTC thermistor, resistance falls predictably as temperature increases. Electronic circuitry can measure this changing resistance and calculate or respond to temperature. Applications include battery monitoring, power supplies, DC/DC converters, charging systems, motor controls, computers, communications equipment, industrial electronics, test equipment, and thermal protection circuits.

The B value describes the thermistor’s resistance-versus-temperature characteristic. This B57321V2103J060 has a nominal B25/50 value of 3940 K, making it suitable for circuits specifically designed around that response curve. Substituting another 10K thermistor with a significantly different B value can result in inaccurate temperature measurements even though both devices measure 10K ohm at 25°C.

The 0603 / 1608 metric package enabled temperature sensing to move directly onto densely populated circuit boards. Small SMD thermistors can be positioned close to processors, regulators, power devices, batteries, and other heat-producing components, providing localized thermal feedback without requiring a larger external sensor.

TDK continues to manufacture this B57321V2-series device, making the B57321V2103J060 an active production component rather than obsolete repair stock.