I. Internal Factors

1. Lifespan Expiration: Tungsten filaments tend to become brittle and break after prolonged use. When using tungsten filaments, it's important to replace aging and brittle filaments.

2. Insufficient Material Strength: The quality of tungsten wire is a critical factor affecting its service life and the likelihood of breaking. Choosing high-quality tungsten wire can effectively reduce the probability of breakage.

3. Overcurrent: Exceeding the power supply's current capacity beyond the tungsten filament's tolerance can lead to filament breakage. When using tungsten filaments, it is essential to determine the current based on the power supply specifications and the filament's tolerance.

II. External Factors

Vibration and Impact: Tungsten filaments are prone to breakage under vibration and impact. During installation, it is essential to avoid exposing tungsten filaments to vibration and impact.

2. Temperature Fluctuations: Changes in temperature can also affect the fracture of tungsten filaments. High temperatures or rapid temperature changes can induce thermal stress in tungsten filaments, leading to fractures. When using tungsten filaments, it is important to control the temperature.

Chemical Corrosion: Certain chemicals can cause corrosion on tungsten wires, making them brittle and prone to breakage. When using tungsten wires, it's important to avoid contact with corrosive substances.

III. Prevention Methods

Choose high-quality tungsten wire.

Maintain the current within the tungsten filament's tolerance.

Avoid vibration and impact to the tungsten wire.

4. Mind the temperature control.

Avoid contact of tungsten filaments with corrosive substances.

In summary, the fracture of tungsten wire is caused by both intrinsic and extrinsic factors. By selecting high-quality tungsten wire and regularly attending to its service life and usage environment, the risk of tungsten wire fracture can be effectively minimized.