Re: switching circuit with multiple power sources

[ my reply was accidentally mailed rather than posted - sorry! ]

In article <nSfHe.1607$Rc6.929@xxxxxxxxxxxxxxxxxxxx>,
Dan Hollands <dhollan3@xxxxxxxxxxxxxxxx> wrote:
]It seems to me a much simpler solution is to just use a 3 pole switch or
]relay

I should have said this needs to be a momentary push-button switch. I
don't think such switches are made to guarantee simultaneous (say within
1 ms) contact across all of the poles. If you press the switch off
center, for instance, the contacts on the side you are pressing on will get
connected first. How much a delay this causes depends on the construction
of the switch and how hard you are pressing.

I am also considering driving the switches with the output of a timer chip
so that I can control precisely how long the terminals are shorted. The
cameras can be set to take multiple exposures if the shutter switch is
held down. That's a lot more difficult to accomplish using a mechanical
switch.

As for relays, electromechanical relays aren't fast enough, and reed or
solid-state relays with multiple poles don't seem to be very easy to
come by (and are certainly going to be a lot more expensive than low-power
transistors).

--

________ Jim Alexander __________________ jalex@xxxxxxxxxxxxx ________________
I have yet to see a problem, however complicated, which, when you looked at it
in the right way, did not become still more complicated. -- Poul Anderson
.

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