One of the common mistakes engineers make is using a diode that is slower
than the transient.  Schottky diodes are a good choice for most
applications.


----- Original Message -----
From: "Olin Lathrop" <olin_piclist@EMBEDINC.COM>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Monday, August 23, 2004 4:25 PM
Subject: Re: [EE:] Commutating diode selection and snubber circuit design
for a solenoid


> Wouter van Ooijen wrote:
> >> If split-second timing is
> >> important, remember that the solenoid will energize as quickly as
> >> before, but it may hang up for a split-second before releasing.
> >
> > If timing is important you can use a zener in series with the diode,
> > or even a resistor. The voltage at the 'low' side of the coil will be
> > higher, so you must decide what the maximum voltage there can be.
>
> Another trick to increase the response time of a relay is to put a
parallel
> capacitor and resistor in series with the relay coil.  Make sure the time
> constant of R*C is less than half or so of the minimum relay on or off
time,
> then set the R so that the steady state current thru the coil is just the
> "holding" current, but not the "pull in" current.  The capacitor initially
> allows more current to flow when the relay is switched on, but the current
> will fall to a lower level once it has been engaged.  This lower current
and
> therefore lower magnetic field is quicker to switch off.
>
>
> *****************************************************************
> Embed Inc, embedded system specialists in Littleton Massachusetts
> (978) 742-9014, http://www.embedinc.com
>
> --
> http://www.piclist.com hint: To leave the PICList
> mailto:piclist-unsubscribe-request@mitvma.mit.edu
>

--
http://www.piclist.com hint: To leave the PICList
mailto:piclist-unsubscribe-request@mitvma.mit.edu