StimJim Isolator

Version 1.00


by William W. Anderson, WinLTP Ltd.


The StimJim_Isolator is a Windows program that controls the StimJim stimulator to act like an intellegent stimulus isolator.  One input pulse from a data acquisition system triggers one isolated mono, bi or triphasic current or voltage pulse from the StimJim.  The 'intellegence' is because the pulse amplitudes can be automatically incremented by clicking one button (figure below).

 The StimJim_Isolator program is free and, like the StimJim, open source.

The 2 channel StimJim was designed by Nate Cermak and Jon Neuman of the Open Ephys group, manufactured by LabMaker, and sold for $645 USD.  The documentation for the StimJim is in the bioRxiv paper (Cermak N, Wilson MA, Schiller J and  Newman JP  (2019)  Stimjim: open source hardware for precise electrical stimulation.  bioRxiv, doi:

Its my understanding that the StimJim from LabMaker is currently out of stock, but that an updated version should be in stock fairly soon.  Check with LabMaker.

I have found only one major limitation with the StimJim – the low compliance voltage of about +13.7 volts.  So a 100 Kohm stimulating electrode can only output a pulse with a maximum of 137 uA.  This means that, in general, the StimJim cannot use the higher resistance metal electrodes like the Haer 30203, but only low and medium resistance electrodes such as the:
1. Haer 30202 and 30213 (Bipolar Concentric, 25um Cone Tip, Platinum/Iridium) Electrodes
2.  50um Platinum/Iridium Bipolar Twisted Wire Electrodes

And with medium resistance electrodes, we found that the StimJim could reliably output 200-300 uA's.
It’s important to realize that the StimJim / StimJim_Isolator is one of the few stimulus isolators that can measure the maximum passible current and electrode resistance during the stimulation pulse when the electrode is in the tissue as well as in the saline.  Using these measurements, we found that:
1. with substantial stimulation, the resistance of new electrodes could about double even with biphasic pulses.
2.  when the stimulating electrode in the saline was pushed into the slice the the resistance could sometimes double or even quadruple (like going from 16 to 69 Kohms).


Download the StimJim Isolator 1.00 Program, Code & Manual here

If you just want to Read the Manual, click here


  Pulse Amplitudes can be Incremented by Clicking One Button

Clicking the 'Enable Incrementing' button causes 5 incrementing pulses to run.  After incrementing finishes the constant amplitude pulses resume.  Incrementing can be stopped at any time by clicking the 'Enable Triggering Constant Pulses' button, or the 'Stop' button.


23 December, 2023