View Single Post
  #51   Report Post  
Posted to sci.electronics.design,alt.binaries.schematics.electronic
Robert Baer[_3_] Robert Baer[_3_] is offline
external usenet poster
 
Posts: 488
Default relay coil inductance

Jim Thompson wrote:
On Sat, 05 Sep 2009 22:28:38 -0700, Robert Baer
wrote:

Jim Thompson wrote:
I haven't done a relay driver circuit for, literally, eons.

Where do I look for reed relays that work on 3.3V supplies with
specications for the coil inductance?

Thanks!

...Jim Thompson

Who cares?
Just use the standard RC snubber across the coil; 100 ohms should be
fine.


You should learn to read... it's a custom chip issue. I posted a link
to a proper solution.

BTW, 100 Ohms and a coil current of 33mA would produce 6.6V (net, 3.3V
supply) on the drain, exceeding the 5.5V maximum operating rating.

...Jim Thompson

100 ohms was a "generic" rough "ballpark" value which you should very
well know; so if you dislike 100 ohms, then use 50 ohms already!