Changing an Autogenerated symbol

Is it possible to change an Autogenerated symbol to a different versions of the symbol? For example, for another type of MOSFET.


Point at the symbol, type Crtl+C. Start a blank symbol(File=>New=>Symbol). Type Ctrl+V. Edit the symbol to your liking. Click on the background in the symbol editor. Type Ctrl+C. Click on the schematic. Type Ctrl+V.

QSPICE should make appropriate looking symbols for native circuit elements(those defined with a .model statement), but for those defined with a .subckt statement, it just draws a box. You can edit the box and pin positions in the schematic which can help readability.


I refer to a symbol that QSPICE already uses. For example, to choose the symbol for a MOSFET, I can click “M” a few times. However, when I add a .model, I have no choice.

The same technique applies. You just also copy and paste a symbol that you like while editing the automatically generated symbol to your liking.

If you need a 4 terminal MOSFET, you can add a pin.

Other than that, I like the concise MOSFET symbol QSPICE uses. For example, I think drawing a body diode on a MOSFET symbol is just clutter. It doesn’t really add meaning. For example, if you ground the gate and source and bring the drain negative of a N polarity MOSFET it will conduct with or without a body diode. It just conducts at the threshold voltage instead of a diode drop(as far as the channel is concerned, the drain is the more positive terminal, not the one labeled DRAIN). Many power FETs work that way. For example, a GaN FET has no body diode. And though not common, there are deployed power Silicon FETs which are lateral on a floating substrate hence no body diode or substrate current. But, sure, it’s nice to have a body diode since it protects the MOSFET due to the lower voltage drop and higher conductivity of the body diode path compared to Rs + Rd and usually lower voltage drop.