I think this is a good example of the practicality, and the style (BOOM!) of The Art of Electronics. This shows very nicely how failing to put a diode across a relay coil can get you into a lot of trouble. Boom, indeed.
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Perplexity AI calculating Zo of a two wire transmission line – comparison
with measurement – updated
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During the process of writing the article Analysis of output matching of a
certain 25W 144MHz PA an estimate was made of the characteristic impedance
Zo of...
5 hours ago
Could never figure out why not build the diode into the relay during manufacture?
ReplyDeleteThere are some selected Omron and others that do have the built-in or "catch" diode.
DeleteSee:
https://www.ia.omron.com/support/faq/answer/36/faq03676/
But, true, the vast majority of DC relays do not.
For DC relays, having it built-in could help reduce EMI during the switch transient, by have a slightly smaller current loop or "antenna" if done properly.
73!