Curious Case of Damped LC Oscillations

112

03:07:58

Open the switch to start.
In this episode of curious case (lol), let's take a look at this LC oscillator. We all know that an ideal LC oscillator is an undamped one, since energy sloshes between the inductor and capacitor undissipated. EC, as we know, has ideal L and C; therefore, the LC Oscillations must be undamped. But that strangely isn't the case. Even though there are no parasitics, the output voltage decays to zero.

published 6 years ago

hurz

6 years ago

you forgot the 10Ω in parallel via the DC source.

hurz

6 years ago

And dont forget everycircuit samplingrate is by far not perfect and needs to slowdown simulation a lot but anyway you will never reach a point of lossless sampling.

hurz

6 years ago

So what is so curious? Looks totaly normal

PrathikP

6 years ago

The 10ohm gets disconnected when the switch is opened.

PrathikP

6 years ago

Did you open the switch or did you just start the sim and see the 0 volts across the LC? When the switch is opened, only the L and C are in the picture. The 10ohm and the voltage source are not.

hurz

6 years ago

Yes, i have opened the switch an can see a damped LC resonance dying out in amplitude. Thats absolut normal and is caused by the limited sampling of calculation everycircuit simulator is doing. place a AC source with a three or even ten times higher frequency and you will see it slows down the simulation but the amplitude reduction is much lower every periode.

hurz

6 years ago

wirh a dummy source i beat everycircuit to sample much faster, at least for the 5kHz source which also helps the rest of the circuit. Now the dampening is much less and takes much longer, but its still present !!!! http://everycircuit.com/circuit/5969056793100288

hurz

6 years ago

These are the basics of time discreet simulation system like everycircuit or any other simulator.

PrathikP

6 years ago

Ah i see now.

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