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Hi to everybody. I believed that using Voltage Controlled Switch was only a matter of giving a digital input to the switch for opening and closing it. But I am not able to obtain it in any way as it seems that VCS is always closed, unregarding the controlled voltage applied to it.

Here is a simple circuit I tried to do: https://www.circuitlab.com/circuit/k34egd/simple-example-with-vcs/

As you can see, output is always equal to 1 V! Please help me. Thanks a lot Giancarlo Perlo - Italy

For an explanation, see:

:)

Thanks a lot, I didn't know it was necessary to use a pull-down resistor!

It isn't necessary but you have to understand exactly what it is you are trying to measure and how the simulation circuit will affect your expected results.

By adding R1 you are in fact making your simulation more realistic. No real switch has an infinite OFF state resistance but similarly, there is no such thing as an open circuit that present an infinite load impedance.

When you start using a simulator you have to get into a way of thinking about what the real world really looks like, how it differs from the theoretical world of textbook problems and simple circuit diagrammatic representations and therefore what your measurements are likely to be.

Welcome to my world.

:)