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A short length of wire that will easily burn out when excessive current flows. The fuse wire may be held in a plastic or glass holder.

Used to protect electronic circuits, normally required to meet regulations for many types of device.

A fuse contains a metal element that will conduct normal currents for operation of the device below the maximum stated current for the fuse.

If current exceeds this rating for a given time the fusible element will heat up and melt, breaking the circuit.

fuse action:

Selection factors:

  1. Normal operating current
  2. Application voltage (AC or DC)
  3. Ambient temperature
  4. Overload current and length in time
  5. Transient operating currents: Start-up or Inrush Currents, Transients or operating modes where currents may be higher than normal operation
  6. Physical size limitations
  7. Agency Approvals or Design Standards
  8. Features
    • mounting type
    • form factor
    • ease of removal
    • axial leads
    • visual indication
    • mounting
    • R.F.I. shielding

Clearing Time

The interval between a specified overcurrent to the final circuit interruption at rated maximum voltage. It is equal to the sum of the melting time plus the arcing time.

Dual Element Fuse

A fuse having responsive elements of two different fusing characteristics in a single series of fuse.

Expulsion Fuse

A vented fuse or fuse unit in which the expulsion effect of gases produced by the arc and the lining of the fuse holder, either alone or aided by a spring, extinguishes the arc.

Single Element Fuse

A fuse having a current responsive element comprising one or more parts with a single fusing characteristic.

See also: Cartridge Fuse, Fusible Link, Over Current Device, Protective Devices, Switchgear.

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Subjects: Electronics

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