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Mutual Inductor

The mut device provides support for mutual inductors. The mut device is never placed. When the mut device is selected in the device menu, rather than selecting a device for placement as do the other selections, a command mode is entered which allows existing inductors to be selected into mutual inductor pairs.

When the mut device is selected, an existing pair of coupled inductors (if any have been defined) is shown highlighted, and the SPICE coupling factor printed. The arrow keys cycle through the internal list of coupled inductor pairs, or a pair may be selected by clicking on one of the inductors or the coefficient label with button 1. At any time, pressing the `a' key will allow addition of a mutual inductor pair. The same effect is obtained by clicking on a non-mutual inductor with button 1. The user is asked to click on the two coupled inductors (if `a' entered or there are no existing mutual inductors), or the second inductor (if the user clicked on an inductor), and then to enter the coupling factor. The coupling factor can be any string, so as to allow shell variable expansion in WRspice, but if it parses as a number it must be in the range between -1 and 1.

Pressing the `d' key will delete the mutual inductance specification for the two inductors currently shown.

Pressing the `k' key will prompt for a new value of the coupling factor for the mutual inductors shown, as will clicking on the coefficient label in a drawing window. When entering the coefficient string, one can enter either the form name=coef_string, or simply the coefficient string. In the first case, the name will provide an alternate fixed name for the mutual inductor in SPICE output. This can be any alphanumeric name, but should start with `k' or `K' for SPICE. If no name is given, Xic will assign a name consisting of K followed by a unique index integer.

One can also change the coefficient string and/or name with the label button in the side menu. Again, the label text can have either of the forms described above.

Pressing the Esc key terminates this (and every) command. One can back out of the operation if necessary with Tab (undo), as usual.


next up previous contents index
Next: Current Source Up: SPICE Devices Previous: Inductor Device   Contents   Index
Stephen R. Whiteley 2017-04-09