# analogous mechanical electrical system- LTSPICE

I have created a basic series and parallel rlc circuit in LTPSICE.
According to this http://lpsa.swarthmore.edu/Analogs/ElectricalMechanicalAnalogs.html and https://www.tutorialspoint.com/control_systems/control_systems_electrical_analogies_mechanical.htm we can see that the output must be same if the values are interchanged.

In the circuit I used an inductor of 1 H, a capacitor of 5 mF and a resistor of 260.8u$$\\Omega\$$ for the series RLC.
For the parallel RLC we have to interchange L and C values and R=1/R as shown in the links. So, R=1/0.0002608, C=1F and L=0.005H. But I am not able to get the same output.

Can somebody help me with it?

The current in series rlc :

The voltage in parallel rlc:

• What is "output"? Voltage? Current? Both? – Dmitry Grigoryev Mar 15 at 11:42
• according to the links the voltage across capacior in series circuit should be equal to current across the inductor in parallel circuit – Bharath raj Mar 15 at 11:47
• Hi Solar Mike, check out the link. I am trying to do a mechanical circuit analogous to electrical. There are 2 methods to do that. And according to the formulas it should be same in 2 methods as shown in tutorialspoint.com/control_systems/… . – Bharath raj Mar 15 at 11:53
• The series RLC has a voltage source (=force input) and the output here is "current" (=velocity), the parallel RLC has a current source (=force input) with output "voltage" (=velocity). The shapes of both outputs should be equal as both represent velocity – Huisman Mar 15 at 12:15
• You are exiting an RC tank which is damped out by R eventually (increase stop time to e.g. 10000 sec). But with the default series resistance in both the inductors, this goes even faster. – Huisman Mar 15 at 12:40