[Premium-Rx] Tantalums and ceramic beads

[73 at 73.am]

The small beads are either ceramic or high-temperature plastic.  In the thru-hole technology of the day (mid 70's through late 80's) the coating on the dipped tantalums that extended to the leads was far from uniform, and the wave-soldering process would put upward pressure on them.  This led to many of the caps being soldered in crooked, or on a cap with no extended insulation, the solder could wick up into the cap itself potentially causing future problems.  Putting a bead on each lead kept the body of the cap away from the holes by a fixed minimum distance, and reduced rework enough to make the cost of installing the beads worthwhile.  The beads themselves cost so little that most manufacturers considered them an overhead expense.   

vy 73 de Paul W8ZO

> On May 8, 2022, at 6:15 PM, W2HX via Premium-Rx <premium-rx at mailman.qth.net> wrote:
> Are they ceramic or ferrite? I would have thought ferrite for some RFI reduction.
> 
> 
> 73 Eugene W2HX
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> -----Original Message-----
> From: premium-rx-bounces at mailman.qth.net <premium-rx-bounces at mailman.qth.net> On Behalf Of Al via Premium-Rx
> Sent: Sunday, May 8, 2022 7:00 PM
> To: premium-rx at mailman.qth.net
> Subject: [Premium-Rx] Tantalums and ceramic beads
> 
> Why are the ceramic beads used when installing tantalum caps?
> 
> Sent from my iPad
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