On Sun, 6 Sep 2009 16:17:09 +0100, "ian field"
wrote:
"John Fields" wrote in message
.. .
On Sat, 05 Sep 2009 11:03:51 -0700, life imitates life
wrote:
On Sat, 05 Sep 2009 12:48:41 -0500, John Fields
wrote:
On Sat, 05 Sep 2009 09:41:06 -0700, 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!
---
That's a toughie.
I can't recall ever seeing inductance data on a spec sheet; I think
you'll probably have to go to the manufacturer for that one.
JF
Would not the real question be why would someone concern himself with the
solenoid inductance of a miniature relay? I could see it if it were
huge.
---
L di
E= ------,
dt
so the diode damping the "spark" when the driver went open would slow
down the opening of the contacts, maybe?
Or maybe the magnetic field building up and breaking down might affect
some nearby component?
Dunno...
JF
ISTR an appnote floating about on the net that recommends using a
combination of diode and zener to clamp the back emf, apparently if you just
clamp it with a single diode, the back emf drives a current round the
diode/solenoid circuit which causes hesitant unlatching.
Ian, Did you miss seeing this...
http://www.analog-innovations.com/SE...elayDriver.pdf
A little better than a flyback diode, and no destructive currents
running in my substrate ;-)
I had to conjure that up from memory... first done so long ago (BC:
before CAD), it only exists somewhere in my paper archives ;-)
...Jim Thompson
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