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Question

Difficulty: EasySoldering Equipment

When assembling electronic circuit boards, which type of solder flux is required to remove surface oxidation without chemically corroding delicate copper conductors?

  1. A
    Acid-core flux
  2. B
    Petroleum paste flux
  3. Rosin-core fluxAnswer
  4. D
    Silicone insulator gel

Answer

Rosin-core flux
Rosin-core flux is specifically formulated for electronic assembly because it cleans tarnish and oxidation during heating to enable wetting, while leaving a harmless, non-corrosive residue on copper conductors.

Step-by-Step Solution

1
Determine the functional requirement for electronic flux
Electronic connections require a flux that cleans oxides at elevated temperatures while leaving an inert residue after cooling.
Oxides prevent molten solder from wetting copper surfaces, but harsh chemicals will destroy thin electronic copper traces.
2
Evaluate flux types based on chemical reactivity and electrical suitability
Rosin flux is formulated specifically for electrical work because it is non-corrosive and non-conductive at room temperature.
Acid-based or active plumbing fluxes permanently corrode copper conductors and create electrical short circuits or open circuits over time.

Key Concept

Selection of rosin-core flux over acid-core flux for non-corrosive electrical soldering.
Estimated Time:40s
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Soldering Equipment

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