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Reply to "Help needed!"

@Buco posted:

... got some TVS's that I was assured would be right for my application.

... part number for the TVS's I purchased is:  SA24A+ TVS DIODE, 500W, 24V, UNIDIR, DO-204AC

Where did you get the advice on component selection?

1) You need a bi-directional (not UNIDIR) TVS.  Unidirectional is generally for DC operation.

2) 24V is too low of a clamping voltage for a RS1 18.5V AC output.  The peak voltage of an 18.5V AC output is over 25V.  So a 24V TVS would be engaged on each AC line cycle in "normal" operation.

See this OGR post for some suitable bi-directional TVS parts.

I'm surprised you didn't see the dreaded magic smoke wafting from the TVS. 

Last edited by stan2004
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