Help Putting XFormers In Spice Please

[kelticwizard]

Oops, my mistake.

I have gotten so accustomed to using either the mouse to copy and paste, or if that doesn't work the browser, that I forgot about the keyboard shortcut. Actually I use the Ctrl-P fairly often, but not the others.

Apparently the mouse or browser does not work with the netlist, just the keyboard shortcut.

Thank you for your help on this.

[kelticwizard]

Hi. I put the following schematic in LT Spice, just to get a bearing on setting up a tuned transformer circuit. So I started out with a simple transformer circuit, not tuned.

I am getting crazy readings, with the voltage between the top of R2 and ground being smooth but the voltage across R2 being very choppy. Moreover, when you change the scale, the voltage across R2 gets even more jagged.

Any suggestions?

[kelticwizard]

When I plot it it looks like below. The green line appears as soon as you put the proble above R2. The jagged blue line appears as soon as you put the proble just ABOVE R1.

Please click on the thumbnail, there actually is a clear image in all that black. Promise.

[kelticwizard]

Moreover, if I change the vertical plot so the bottom number is -3600mdB, (corresponding to -3.6 dB), the blue line seems to get more ragged to accommodate the scale. It seems to get increase it's raggedness by an order of magnitude when the scale is changed. Now the raggedness of the blue line, (which I assume is the voltage amplitude of R2), is now dropping down to nearly -3.6 dB at 4.5 KHz.

All this is happening in the Bode decibel plot.

By the way, here is the netlist.

* C:\Program Files\LTC\SwCADIII\Draft9.asc
V1 N001 0 AC 1
L1 N001 0 1
L2 N002 N003 1
R1 N003 0 10Meg
R2 N002 N003 10K
K12 L1 L2 0.99
.ac oct 1000 10 20000
.backanno
.end


I'm sure there is a simple error I am making. Could anyone tell me what it is?

[jcx]

the jagged line is actually the phase of the current thru R1 (look closely and you can see it is a dashed line, you can turn off phase plotting by left cliking in the waveform plot right vert margin when you see the ruler)

since the current thru R1 is already numerical noise @ ~ -400 dB (in my recreation of your sim) there is actually no problem, its just that the R1 numerical noise phase trace has a visible on screen magnitude

[kelticwizard]

Excellent. Thank you very much.

So the green line is the voltage through R2 after all.