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Hi I am a new user to circuitlab. I have built an FM circuit and when I try to conduct a frequency-domain simulation of this circuit, it shows an error. May I know what is wrong with this circuit? Any help would be appreciated. Thanks!!

Here is the URL:https://www.circuitlab.com/circuit/77rzvf/fmradio/

Your circuit:

has no signal source.

You need to add a signal source for the AC sweep and somehow couple it in to wherever your antenna would be connected.

The easiest way to do this may be to use a current source rather than a voltage source to inject a small current into the circuit. This may be a better model of how the real signal is coupled in from an antenna and avoids loading the tuned circuit.

You will have to work out how small this current is to represent the signals in a real receiver.

A couple of other points:

i) Your circuit also has a power source which must be connected at the time the simulation is run. For an AC sweep it is probably simplest to delete the on/off switch and show the battery hardwired in place.

ii) You cannot represent a tapped inductor the way you have drawn L2. You will see that there is no wire join dot where you have drawn the wire to on it.

If L2 is centre tapped, the best way to do it in CL is to use the simple two winding transformer and set it up with a 1:1 turns ratio and the primary inductance to be the total inductance of the whole of L2 divided by 4.

Then connect the dotted end of the primary to the undotted end of the secondary and use that as the centre tap connection.

If L2 is not centre tapped, the same idea applies but you will have to work out the inductances of the primary and then the turn ratio that will give you the correct overall, end to end inductance.

BTW: just post the link,

https://www.circuitlab.com/circuit/77rzvf/fmradio/

don't prefix it with an intro.

Better still, use the Circuit Lab link as above to show the circuit in your post.

See:

for help on how to use the transformer in CL.

Thank you very much for your help. Really appreciate it!

These might help too:

and:

https://www.circuitlab.com/forums/support/topic/48ywk83s/run-ac-sweep-with-input-voltage-other-then-1v/

OTOH; they may just confuse ...

:)

And ...

https://www.circuitlab.com/forums/modeling-and-simulation/topic/75exru43/coupling-inductors/