TopBand: Remote Beverage Switching

[Larry Kayser]

Bill wrote about back emf from a relay as the voltage is removed...
>I once ran some scope tests on suppressed vs. unsuppressed relay coil
>transients.  The results were startling - an unsuppressed 28 vdc
>hermetically sealed aircraft relay can easily generate 600 volt spikes
>at the coil terminals.  The addition of a back-biased diode across the
>coil nearly eliminates the spike.

This is not without a penalty however.  The relay will be MUCH MUCH slower
in release time with the diode across the coil terminals.

Larry
va3lk / wa3zia


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