At 03:23 PM 2/9/2006 +1300, you wrote:


>If switching speed is important I'd look at using a TVS across the
>relay coil (in place of the diode)

You'd have to use a diode in series with the TVS or a bidirectional
TVS. In the latter case you'd have less flexibility on the voltage
rating, since it would have to be less than the maximum supply voltage
under all possible conditions, lest the transistor prematurely ring up
the curtain and joint the choir invisible.

Simplest (and noisiest) solution is to use an avalanche-rated MOSFET.

>Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com
->> Inexpensive test equipment & parts http://search.ebay.com/_W0QQsassZspeff


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