Is alloy resistance better than metal film resistance?

The performance comparison between alloy resistors and metal film resistors needs to be analyzed in conjunction with specific application scenarios, as each has its own advantages:
The core advantages of alloy resistors are:
Higher power density: typically 3-5 W/mm ² (metal film about 1-2 W/mm ²)
Stronger overload capacity: can withstand 10 times the rated power impact (metal film usually 5 times)
Temperature stability: Some alloys (such as manganese copper) have extremely low temperature coefficients (<20ppm/℃)
Surge resistance characteristics: more suitable for transient high current scenarios such as motor start-up and power short circuit
The core advantages of metal film resistors are:
Higher accuracy: can achieve a precision of 0.1% (alloys usually start at 1%)
Lower noise:<5nV/√ Hz (suitable for precision measurement circuits)
Frequency characteristics: Better high-frequency response (lower parasitic inductance)
Environmental adaptability: Resistance to vulcanization/moisture can be achieved through special coatings (such as EAM25FS series)
Selection decision tree:
Applications with current ≥ 5A → Prioritize alloy resistors (such as battery protection boards)
Current<3A and requires precise detection → Choose a metal film resistor (such as a current sensor)
Working temperature>125 ℃ → Alloy resistance is more reliable (metal film may undergo film diffusion)
Cost sensitive design → Metal film resistors offer higher cost-effectiveness (30-50% cheaper for the same specifications)
Typical application cases:
Alloy resistance: BMS discharge protection, motor phase current detection, industrial power overcurrent protection
Metal film resistors: precision voltage reference, audio amplifier feedback network, medical equipment signal conditioning
It is recommended to weigh the current/voltage parameters, ambient temperature, and cost budget of the specific circuit, and if necessary, contact the resistor manufacturer to obtain a complete derating curve and failure mode analysis report.