Enrico wrote, "I cannot understad the functionality of this statements. Nothing from help, could someone explain that?"
When a switch is "on" it means the switch is closed, or the switch contacts are closed or connected. ?A connection is made through the switch. ?The switch is in the state where it has a low resistance.
When a switch is "off" it is the opposite. ?The switch is open, with a high resistance.
For LTspice's switch model, "on" and "off" only mean the two states of the switch. ?You could have the model work "backwards", so that the "on" condition is the high resistance state.
I thank you Andy, but i've made a small circuit with one switch ON and another OFF and they work exactly the same, so i don't understand the difference. Enrico
? "I thank you Andy, but i've made a small circuit with one switch ON and another OFF and they work exactly the same, so i don't understand the difference."
Both S1 and S2 switches are controlled from the same voltage, 'b'. ?So they must work exactly the same.
I believe the optional "on" and "off" parameters, with the Switch device, are aides or hints to LTspice, about its initial conditions. ?Occasionally, SPICE has difficulty figuring out whether a device such as a diode or a transistor should initially be ON or OFF when it does the initial transient solution. ?Adding that parameter is used as an initial guess, to help LTspice decide whether the switch (or diode or transistor) should initially be ON. ?Other than making it easier to solve for the initial conditions, it does not affect the rest of the simulation. ?Ultimately (except for that initial guess), the state of the switch is determined only by its control voltage.
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