Simulating SPST and SPDT switches?

Question

I've spent a few hours over the last couple of days trying to design a realistic and easy-to-handle simulation for break-before-make toggle switches. But I imagine this is re-inventing the wheel, as there must be well-established techniques. I'm using Circuitmaker, but I assume the principles must be similar in other programs.

My approach so far (to the more complex case of a SPDT switch) has been to use two VCSs, a triangle wave input (inverted before applying to the 2nd VCS), and altering the respective VCS's Threshold values to get the 'break-before-make' delay. But I expect I'm making heavy weather of it, and would be grateful for shared techniques please.

Jim Thompson · Accepted Answer

That's about the only way to attack it.                                        ...Jim Thompson-- |  James E.Thompson, P.E.                           |    mens     ||  Analog Innovations, Inc.                         |     et      ||  Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    ||  Phoenix, Arizona            Voice:(480)460-2350  |             ||  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  ||                  |    1962     |             I love to cook with wine.      Sometimes I even put it in the food.

Terry Pinnell · Answer

I've spent a few hours over the last couple of days trying to design a realistic and easy-to-handle simulation for break-before-make toggle switches. But I imagine this is re-inventing the wheel, as there must be well-established techniques. I'm using Circuitmaker, but I assume the principles must be similar in other programs.

My approach so far (to the more complex case of a SPDT switch) has been to use two VCSs, a triangle wave input (inverted before applying to the 2nd VCS), and altering the respective VCS's Threshold values to get the 'break-before-make' delay. But I expect I'm making heavy weather of it, and would be grateful for shared techniques please.

Terry Pinnell · Answer

As I suspected, once I started thinking straight, this turned out to be pretty simple. For a SPDT, with about 40 ms between break and make, I'm using this arrangement:

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Anyone have any suggested alternatives please?

Terry Pinnell · Answer

Thanks. See also my later reply. Does that design look OK?-- Terry PinnellHobbyist, West Sussex, UK

Simulating SPST and SPDT switches?

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