Question T7D08
From subelement T7 - T7D
Which of the following types of solder should not be used for radio and electronic applications?
Why is this correct?
Acid-core solder (A) should never be used for radio and electronic applications because it leaves acidic residue that corrodes connections over time, degrading performance and reliability. Lead-tin solder (B) is traditional and acceptable for electronics. Rosin-core solder (C) is specifically recommended for electronics because rosin flux cleans oxidation without leaving corrosive residue. Tin-copper solder (D) is a modern lead-free alternative that's also suitable for electronic work.
Memory tip
Remember the pattern: anything with 'acid' in electronics is usually bad news. Acid attacks metal connections over time. Look for 'rosin-core' as the electronics-friendly choice in solder questions — rosin is non-corrosive and designed for delicate electronic components.
Learn more
Acid-core solder uses flux containing acids that effectively clean heavily oxidized or dirty metals, making it ideal for plumbing and sheet metal work. However, these same acids continue their corrosive action after the joint cools, gradually eating away at the fine copper traces on circuit boards and component leads. This creates high-resistance connections that can cause intermittent failures or complete circuit breakdown over months or years of operation.
Think about it
Why do you think plumbers use acid-core solder successfully while electronics technicians avoid it completely?