# 6. User FAQ¶

## 6.1. How to get help or report an issue ?¶

There is no mailing list or forum actually, so you can either contact me or fill an issue on Github.

## 6.2. How to typeset u_kΩ or u_μV in Python code ?¶

There is three solutions if you don’t have these Unicode characters available on your keyboard. The first one, is to use the ASCII alternative: u_kOhm or u_uV.. The second one, is to define macros on your favourite editor. The last one, is to customise your keyboard settings (If your on Linux look at https://www.x.org/wiki/XKB/).

## 6.3. How to set the Ngspice library path ?¶

If the setting doesn’t match your environment, then you have to set manually the attribute PySpice.Spice.NgSpice.Shared.NgSpiceShared.LIBRARY_PATH. Note you have to place a brace pair just before the extension, for example “C:…ngspice{}.dll”. You can also fix the value of PySpice.Spice.NgSpice.Shared.NgSpiceShared.NGSPICE_PATH.

## 6.4. How to set the Ngspice path ?¶

If the setting doesn’t match your environment, then you have to set manually the attribute PySpice.Spice.Server.SpiceServer.SPICE_COMMAND. This value can be passed as argument as well, see API documentation.

## 6.5. Is ground node required ?¶

Yes, according to Ngspice manual, each circuit has to have a ground node (gnd or 0)!

## 6.6. How to set the simulator ?¶

You can set globally the default simulator using the attribute PySpice.Spice.Simulation.CircuitSimulator.DEFAULT_SIMULATOR.

Else you can set the simulator per simulation using the simulator option:

simulator = circuit.simulator(simulator='...')


Actually, theses simulators are available:

• ngspice-subprocess
• ngspice-shared
• xyce-serial
• xyce-parallel

## 6.7. Is Xyce 100% compatible with SPICE ?¶

No, you have to read the user guide and reference manual to learn what are the actual differences!

In particular, the device models provided by vendors could need to be adapted for Xyce.

Notice, you can add the suffix @xyce to a .lib or .mod file in order to have a special version for Xyce, for example BAV21.lib@xyce. The PySpice Library Manager will include this special version if it found one that correspond to the simulator used for the current simulation.

PySpice will try to incrementally provide a generic interface in the future.