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Electric Circuits: Turn Current Source Off At Specific Time

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Hello, I am modeling a circuit in Comsol 5.6 using the Electric Circuit physics and Time Dependent solver which I am simulating for 1 microsecond. Ideally, the sinusoidal current source would only be on for 50 nanoseconds so we can observe how the signals in the circuit decay after the current source has been stopped. However, at this time I can't find a way for a current or voltage source to be on for only a fraction of the simulation time. Does anyone know if this is possible?


2 Replies Last Post 15.03.2023, 13:33 GMT-4

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Posted: 1 year ago 15.03.2023, 11:14 GMT-4

In v56 of comsol in the electric circuits interface there is a "switch" circuit element. I have not used this element but it looks configurable to toggle on/off. My suggestion would be to do a simple transient simulation with maybe a source, series switch, and load resistor. Setup the transient simulation to work without the switch to know that portion works and then apply the switch. I do not have guidance in using the switch but I think you could either use on or off conditions or maybe use a pulse source to turn the switch on/off.

In v56 of comsol in the electric circuits interface there is a "switch" circuit element. I have not used this element but it looks configurable to toggle on/off. My suggestion would be to do a simple transient simulation with maybe a source, series switch, and load resistor. Setup the transient simulation to work without the switch to know that portion works and then apply the switch. I do not have guidance in using the switch but I think you could either use on or off conditions or maybe use a pulse source to turn the switch on/off.

Dave Greve Certified Consultant

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Posted: 1 year ago 15.03.2023, 13:33 GMT-4

The value of a current or voltage source can be any function that Comsol knows about. For example v0sin(2pift)*(t<1/f).

Using a switch can be problematic. A current source shorted by a switch is just a short (not a zero value current source). A current source isolated by an open switch has (theoretically) an infinite voltage which may give Comsol problems.

The value of a current or voltage source can be any function that Comsol knows about. For example v0*sin(2*pi*f*t)*(t

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