The MF72 series 18D-15 is a directly heated, power-type negative temperature coefficient thermistor designed for inrush current suppression. Its rated zero-power resistance is 18Ω ± 20%, verified by 1.5VDC testing at 25°C. A material constant B value of 2950K ± 10% ensures consistent temperature response. A thermal time constant of approximately 86 seconds and a dissipation factor of approximately 18mW/°C combine to create a heat capacity specification of 1548mJ/°C, ensuring surge protection reliability. It offers a maximum steady-state current of 4A and a low residual resistance of 0.288Ω, supporting capacitive loads of 330μF for 240V systems or 1200μF for 120V systems. The device features a standardized design with a diameter of 17.5mm and a thickness of 6mm. Four lead configurations are available: inward-curved, outward-curved, side-curved, and straight-curved. The phenolic resin package and CP wire leads ensure mechanical stability, and the operating temperature range covers harsh environments from -40°C to +200°C.
It is mainly used in electronic energy-saving lamps, cathode ray tube display power supplies and industrial heating equipment, optimizing system startup performance through high B value and precise thermal response characteristics.