Electrical Fuse Wire Diameter Calculation

What is the diameter of the wire in a certain fuse that blows if the current exceeds 1.0 A and melts with a current density of 620 A/cm^2?

Answer:

The diameter of the wire in the fuse is 0.45 mm.

Given the data:

  • Current in the fuse: 1 Ampere
  • Current density: 620 A/cm²

To calculate the diameter of the wire in the fuse, we use the formula:

Area of the wire = Current / Current density

Area = 1 / 620 = 1.613 x 10⁻³ cm²

Since 10000 cm² = 1 m², 1.613 x 10⁻³ cm² = 1.613 x 10⁻⁷ m²

The area of the wire can be calculated using the formula:

Area = πd² / 4, where d is the diameter of the wire

Substitute the values into the equation:

1.613 x 10⁻⁷ = (3.14 x d²) / 4

6.448 x 10⁻⁷ = 3.142 x d²

Solving for d: d² = 2.05 x 10⁻⁴, d = √(2.05 x 10⁻⁷) = 4.5 x 10⁻⁴ m = 0.45 mm

Therefore, the diameter of the wire in the fuse is 0.45 mm.

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