At 11:18 AM 8/2/01 +0100, you wrote:
>If it's a triac device it will only work on AC, as the triac will stay
>conducting until the current crosses zero.

While this is correct there might be situations where you could use the
behavior to advantage on DC. Shorting the output with a momentary
switch (or interrupting the current) will turn it off ( assuming dv/dt isn't
too high). So, for a security alarm powered from a 12VDC battery, it might
be just what you want.

Another possible use on DC would be as a cheap isolated way to control
high voltage relatively low currents.. 10's of uA, say.  With a high value
series resistor between, say +300 and -300 VDC you could get an isolated
600V swing from your micro etc. with a very cheap little devices. This
works because the current is less than the holding current (confirm this
at maximum Ta).

Best regards,
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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
Contributions invited->The AVR-gcc FAQ is at: http://www.bluecollarlinux.com
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